jupystar/dist/index.js

Converter from Jupyter notebook (ipynb) to Starboard notebook

const Char = {
  ANCHOR: '&',
  COMMENT: '#',
  TAG: '!',
  DIRECTIVES_END: '-',
  DOCUMENT_END: '.'
};
const LogLevel = Object.assign(['silent', 'error', 'warn', 'debug'], {
  SILENT: 0,
  ERROR: 1,
  WARN: 2,
  DEBUG: 3
});
const Type = {
  ALIAS: 'ALIAS',
  BLANK_LINE: 'BLANK_LINE',
  BLOCK_FOLDED: 'BLOCK_FOLDED',
  BLOCK_LITERAL: 'BLOCK_LITERAL',
  COMMENT: 'COMMENT',
  DIRECTIVE: 'DIRECTIVE',
  DOCUMENT: 'DOCUMENT',
  FLOW_MAP: 'FLOW_MAP',
  FLOW_SEQ: 'FLOW_SEQ',
  MAP: 'MAP',
  MAP_KEY: 'MAP_KEY',
  MAP_VALUE: 'MAP_VALUE',
  PLAIN: 'PLAIN',
  QUOTE_DOUBLE: 'QUOTE_DOUBLE',
  QUOTE_SINGLE: 'QUOTE_SINGLE',
  SEQ: 'SEQ',
  SEQ_ITEM: 'SEQ_ITEM'
};
const defaultTagPrefix = 'tag:yaml.org,2002:';
const defaultTags = {
  MAP: 'tag:yaml.org,2002:map',
  SEQ: 'tag:yaml.org,2002:seq',
  STR: 'tag:yaml.org,2002:str'
};

var Char_1 = Char;
var LogLevel_1 = LogLevel;
var Type_1 = Type;
var defaultTagPrefix_1 = defaultTagPrefix;
var defaultTags_1 = defaultTags;

var constants = {
	Char: Char_1,
	LogLevel: LogLevel_1,
	Type: Type_1,
	defaultTagPrefix: defaultTagPrefix_1,
	defaultTags: defaultTags_1
};

function findLineStarts(src) {
  const ls = [0];
  let offset = src.indexOf('\n');

  while (offset !== -1) {
    offset += 1;
    ls.push(offset);
    offset = src.indexOf('\n', offset);
  }

  return ls;
}

function getSrcInfo(cst) {
  let lineStarts, src;

  if (typeof cst === 'string') {
    lineStarts = findLineStarts(cst);
    src = cst;
  } else {
    if (Array.isArray(cst)) cst = cst[0];

    if (cst && cst.context) {
      if (!cst.lineStarts) cst.lineStarts = findLineStarts(cst.context.src);
      lineStarts = cst.lineStarts;
      src = cst.context.src;
    }
  }

  return {
    lineStarts,
    src
  };
}
/**
 * @typedef {Object} LinePos - One-indexed position in the source
 * @property {number} line
 * @property {number} col
 */

/**
 * Determine the line/col position matching a character offset.
 *
 * Accepts a source string or a CST document as the second parameter. With
 * the latter, starting indices for lines are cached in the document as
 * `lineStarts: number[]`.
 *
 * Returns a one-indexed `{ line, col }` location if found, or
 * `undefined` otherwise.
 *
 * @param {number} offset
 * @param {string|Document|Document[]} cst
 * @returns {?LinePos}
 */


function getLinePos(offset, cst) {
  if (typeof offset !== 'number' || offset < 0) return null;
  const {
    lineStarts,
    src
  } = getSrcInfo(cst);
  if (!lineStarts || !src || offset > src.length) return null;

  for (let i = 0; i < lineStarts.length; ++i) {
    const start = lineStarts[i];

    if (offset < start) {
      return {
        line: i,
        col: offset - lineStarts[i - 1] + 1
      };
    }

    if (offset === start) return {
      line: i + 1,
      col: 1
    };
  }

  const line = lineStarts.length;
  return {
    line,
    col: offset - lineStarts[line - 1] + 1
  };
}
/**
 * Get a specified line from the source.
 *
 * Accepts a source string or a CST document as the second parameter. With
 * the latter, starting indices for lines are cached in the document as
 * `lineStarts: number[]`.
 *
 * Returns the line as a string if found, or `null` otherwise.
 *
 * @param {number} line One-indexed line number
 * @param {string|Document|Document[]} cst
 * @returns {?string}
 */

function getLine(line, cst) {
  const {
    lineStarts,
    src
  } = getSrcInfo(cst);
  if (!lineStarts || !(line >= 1) || line > lineStarts.length) return null;
  const start = lineStarts[line - 1];
  let end = lineStarts[line]; // undefined for last line; that's ok for slice()

  while (end && end > start && src[end - 1] === '\n') --end;

  return src.slice(start, end);
}
/**
 * Pretty-print the starting line from the source indicated by the range `pos`
 *
 * Trims output to `maxWidth` chars while keeping the starting column visible,
 * using `…` at either end to indicate dropped characters.
 *
 * Returns a two-line string (or `null`) with `\n` as separator; the second line
 * will hold appropriately indented `^` marks indicating the column range.
 *
 * @param {Object} pos
 * @param {LinePos} pos.start
 * @param {LinePos} [pos.end]
 * @param {string|Document|Document[]*} cst
 * @param {number} [maxWidth=80]
 * @returns {?string}
 */

function getPrettyContext({
  start,
  end
}, cst, maxWidth = 80) {
  let src = getLine(start.line, cst);
  if (!src) return null;
  let {
    col
  } = start;

  if (src.length > maxWidth) {
    if (col <= maxWidth - 10) {
      src = src.substr(0, maxWidth - 1) + '…';
    } else {
      const halfWidth = Math.round(maxWidth / 2);
      if (src.length > col + halfWidth) src = src.substr(0, col + halfWidth - 1) + '…';
      col -= src.length - maxWidth;
      src = '…' + src.substr(1 - maxWidth);
    }
  }

  let errLen = 1;
  let errEnd = '';

  if (end) {
    if (end.line === start.line && col + (end.col - start.col) <= maxWidth + 1) {
      errLen = end.col - start.col;
    } else {
      errLen = Math.min(src.length + 1, maxWidth) - col;
      errEnd = '…';
    }
  }

  const offset = col > 1 ? ' '.repeat(col - 1) : '';
  const err = '^'.repeat(errLen);
  return `${src}\n${offset}${err}${errEnd}`;
}

var getLine_1 = getLine;
var getLinePos_1 = getLinePos;
var getPrettyContext_1 = getPrettyContext;

var sourceUtils = {
	getLine: getLine_1,
	getLinePos: getLinePos_1,
	getPrettyContext: getPrettyContext_1
};

class Range {
  static copy(orig) {
    return new Range(orig.start, orig.end);
  }

  constructor(start, end) {
    this.start = start;
    this.end = end || start;
  }

  isEmpty() {
    return typeof this.start !== 'number' || !this.end || this.end <= this.start;
  }
  /**
   * Set `origStart` and `origEnd` to point to the original source range for
   * this node, which may differ due to dropped CR characters.
   *
   * @param {number[]} cr - Positions of dropped CR characters
   * @param {number} offset - Starting index of `cr` from the last call
   * @returns {number} - The next offset, matching the one found for `origStart`
   */


  setOrigRange(cr, offset) {
    const {
      start,
      end
    } = this;

    if (cr.length === 0 || end <= cr[0]) {
      this.origStart = start;
      this.origEnd = end;
      return offset;
    }

    let i = offset;

    while (i < cr.length) {
      if (cr[i] > start) break;else ++i;
    }

    this.origStart = start + i;
    const nextOffset = i;

    while (i < cr.length) {
      // if end was at \n, it should now be at \r
      if (cr[i] >= end) break;else ++i;
    }

    this.origEnd = end + i;
    return nextOffset;
  }

}

var Range_2 = Range;

var Range_1 = {
	Range: Range_2
};

/** Root class of all nodes */

class Node {
  static addStringTerminator(src, offset, str) {
    if (str[str.length - 1] === '\n') return str;
    const next = Node.endOfWhiteSpace(src, offset);
    return next >= src.length || src[next] === '\n' ? str + '\n' : str;
  } // ^(---|...)


  static atDocumentBoundary(src, offset, sep) {
    const ch0 = src[offset];
    if (!ch0) return true;
    const prev = src[offset - 1];
    if (prev && prev !== '\n') return false;

    if (sep) {
      if (ch0 !== sep) return false;
    } else {
      if (ch0 !== constants.Char.DIRECTIVES_END && ch0 !== constants.Char.DOCUMENT_END) return false;
    }

    const ch1 = src[offset + 1];
    const ch2 = src[offset + 2];
    if (ch1 !== ch0 || ch2 !== ch0) return false;
    const ch3 = src[offset + 3];
    return !ch3 || ch3 === '\n' || ch3 === '\t' || ch3 === ' ';
  }

  static endOfIdentifier(src, offset) {
    let ch = src[offset];
    const isVerbatim = ch === '<';
    const notOk = isVerbatim ? ['\n', '\t', ' ', '>'] : ['\n', '\t', ' ', '[', ']', '{', '}', ','];

    while (ch && notOk.indexOf(ch) === -1) ch = src[offset += 1];

    if (isVerbatim && ch === '>') offset += 1;
    return offset;
  }

  static endOfIndent(src, offset) {
    let ch = src[offset];

    while (ch === ' ') ch = src[offset += 1];

    return offset;
  }

  static endOfLine(src, offset) {
    let ch = src[offset];

    while (ch && ch !== '\n') ch = src[offset += 1];

    return offset;
  }

  static endOfWhiteSpace(src, offset) {
    let ch = src[offset];

    while (ch === '\t' || ch === ' ') ch = src[offset += 1];

    return offset;
  }

  static startOfLine(src, offset) {
    let ch = src[offset - 1];
    if (ch === '\n') return offset;

    while (ch && ch !== '\n') ch = src[offset -= 1];

    return offset + 1;
  }
  /**
   * End of indentation, or null if the line's indent level is not more
   * than `indent`
   *
   * @param {string} src
   * @param {number} indent
   * @param {number} lineStart
   * @returns {?number}
   */


  static endOfBlockIndent(src, indent, lineStart) {
    const inEnd = Node.endOfIndent(src, lineStart);

    if (inEnd > lineStart + indent) {
      return inEnd;
    } else {
      const wsEnd = Node.endOfWhiteSpace(src, inEnd);
      const ch = src[wsEnd];
      if (!ch || ch === '\n') return wsEnd;
    }

    return null;
  }

  static atBlank(src, offset, endAsBlank) {
    const ch = src[offset];
    return ch === '\n' || ch === '\t' || ch === ' ' || endAsBlank && !ch;
  }

  static nextNodeIsIndented(ch, indentDiff, indicatorAsIndent) {
    if (!ch || indentDiff < 0) return false;
    if (indentDiff > 0) return true;
    return indicatorAsIndent && ch === '-';
  } // should be at line or string end, or at next non-whitespace char


  static normalizeOffset(src, offset) {
    const ch = src[offset];
    return !ch ? offset : ch !== '\n' && src[offset - 1] === '\n' ? offset - 1 : Node.endOfWhiteSpace(src, offset);
  } // fold single newline into space, multiple newlines to N - 1 newlines
  // presumes src[offset] === '\n'


  static foldNewline(src, offset, indent) {
    let inCount = 0;
    let error = false;
    let fold = '';
    let ch = src[offset + 1];

    while (ch === ' ' || ch === '\t' || ch === '\n') {
      switch (ch) {
        case '\n':
          inCount = 0;
          offset += 1;
          fold += '\n';
          break;

        case '\t':
          if (inCount <= indent) error = true;
          offset = Node.endOfWhiteSpace(src, offset + 2) - 1;
          break;

        case ' ':
          inCount += 1;
          offset += 1;
          break;
      }

      ch = src[offset + 1];
    }

    if (!fold) fold = ' ';
    if (ch && inCount <= indent) error = true;
    return {
      fold,
      offset,
      error
    };
  }

  constructor(type, props, context) {
    Object.defineProperty(this, 'context', {
      value: context || null,
      writable: true
    });
    this.error = null;
    this.range = null;
    this.valueRange = null;
    this.props = props || [];
    this.type = type;
    this.value = null;
  }

  getPropValue(idx, key, skipKey) {
    if (!this.context) return null;
    const {
      src
    } = this.context;
    const prop = this.props[idx];
    return prop && src[prop.start] === key ? src.slice(prop.start + (skipKey ? 1 : 0), prop.end) : null;
  }

  get anchor() {
    for (let i = 0; i < this.props.length; ++i) {
      const anchor = this.getPropValue(i, constants.Char.ANCHOR, true);
      if (anchor != null) return anchor;
    }

    return null;
  }

  get comment() {
    const comments = [];

    for (let i = 0; i < this.props.length; ++i) {
      const comment = this.getPropValue(i, constants.Char.COMMENT, true);
      if (comment != null) comments.push(comment);
    }

    return comments.length > 0 ? comments.join('\n') : null;
  }

  commentHasRequiredWhitespace(start) {
    const {
      src
    } = this.context;
    if (this.header && start === this.header.end) return false;
    if (!this.valueRange) return false;
    const {
      end
    } = this.valueRange;
    return start !== end || Node.atBlank(src, end - 1);
  }

  get hasComment() {
    if (this.context) {
      const {
        src
      } = this.context;

      for (let i = 0; i < this.props.length; ++i) {
        if (src[this.props[i].start] === constants.Char.COMMENT) return true;
      }
    }

    return false;
  }

  get hasProps() {
    if (this.context) {
      const {
        src
      } = this.context;

      for (let i = 0; i < this.props.length; ++i) {
        if (src[this.props[i].start] !== constants.Char.COMMENT) return true;
      }
    }

    return false;
  }

  get includesTrailingLines() {
    return false;
  }

  get jsonLike() {
    const jsonLikeTypes = [constants.Type.FLOW_MAP, constants.Type.FLOW_SEQ, constants.Type.QUOTE_DOUBLE, constants.Type.QUOTE_SINGLE];
    return jsonLikeTypes.indexOf(this.type) !== -1;
  }

  get rangeAsLinePos() {
    if (!this.range || !this.context) return undefined;
    const start = sourceUtils.getLinePos(this.range.start, this.context.root);
    if (!start) return undefined;
    const end = sourceUtils.getLinePos(this.range.end, this.context.root);
    return {
      start,
      end
    };
  }

  get rawValue() {
    if (!this.valueRange || !this.context) return null;
    const {
      start,
      end
    } = this.valueRange;
    return this.context.src.slice(start, end);
  }

  get tag() {
    for (let i = 0; i < this.props.length; ++i) {
      const tag = this.getPropValue(i, constants.Char.TAG, false);

      if (tag != null) {
        if (tag[1] === '<') {
          return {
            verbatim: tag.slice(2, -1)
          };
        } else {
          // eslint-disable-next-line no-unused-vars
          const [_, handle, suffix] = tag.match(/^(.*!)([^!]*)$/);
          return {
            handle,
            suffix
          };
        }
      }
    }

    return null;
  }

  get valueRangeContainsNewline() {
    if (!this.valueRange || !this.context) return false;
    const {
      start,
      end
    } = this.valueRange;
    const {
      src
    } = this.context;

    for (let i = start; i < end; ++i) {
      if (src[i] === '\n') return true;
    }

    return false;
  }

  parseComment(start) {
    const {
      src
    } = this.context;

    if (src[start] === constants.Char.COMMENT) {
      const end = Node.endOfLine(src, start + 1);
      const commentRange = new Range_1.Range(start, end);
      this.props.push(commentRange);
      return end;
    }

    return start;
  }
  /**
   * Populates the `origStart` and `origEnd` values of all ranges for this
   * node. Extended by child classes to handle descendant nodes.
   *
   * @param {number[]} cr - Positions of dropped CR characters
   * @param {number} offset - Starting index of `cr` from the last call
   * @returns {number} - The next offset, matching the one found for `origStart`
   */


  setOrigRanges(cr, offset) {
    if (this.range) offset = this.range.setOrigRange(cr, offset);
    if (this.valueRange) this.valueRange.setOrigRange(cr, offset);
    this.props.forEach(prop => prop.setOrigRange(cr, offset));
    return offset;
  }

  toString() {
    const {
      context: {
        src
      },
      range,
      value
    } = this;
    if (value != null) return value;
    const str = src.slice(range.start, range.end);
    return Node.addStringTerminator(src, range.end, str);
  }

}

var Node_2 = Node;

var Node_1 = {
	Node: Node_2
};

class YAMLError extends Error {
  constructor(name, source, message) {
    if (!message || !(source instanceof Node_1.Node)) throw new Error(`Invalid arguments for new ${name}`);
    super();
    this.name = name;
    this.message = message;
    this.source = source;
  }

  makePretty() {
    if (!this.source) return;
    this.nodeType = this.source.type;
    const cst = this.source.context && this.source.context.root;

    if (typeof this.offset === 'number') {
      this.range = new Range_1.Range(this.offset, this.offset + 1);
      const start = cst && sourceUtils.getLinePos(this.offset, cst);

      if (start) {
        const end = {
          line: start.line,
          col: start.col + 1
        };
        this.linePos = {
          start,
          end
        };
      }

      delete this.offset;
    } else {
      this.range = this.source.range;
      this.linePos = this.source.rangeAsLinePos;
    }

    if (this.linePos) {
      const {
        line,
        col
      } = this.linePos.start;
      this.message += ` at line ${line}, column ${col}`;
      const ctx = cst && sourceUtils.getPrettyContext(this.linePos, cst);
      if (ctx) this.message += `:\n\n${ctx}\n`;
    }

    delete this.source;
  }

}
class YAMLReferenceError extends YAMLError {
  constructor(source, message) {
    super('YAMLReferenceError', source, message);
  }

}
class YAMLSemanticError extends YAMLError {
  constructor(source, message) {
    super('YAMLSemanticError', source, message);
  }

}
class YAMLSyntaxError extends YAMLError {
  constructor(source, message) {
    super('YAMLSyntaxError', source, message);
  }

}
class YAMLWarning extends YAMLError {
  constructor(source, message) {
    super('YAMLWarning', source, message);
  }

}

var YAMLError_1 = YAMLError;
var YAMLReferenceError_1 = YAMLReferenceError;
var YAMLSemanticError_1 = YAMLSemanticError;
var YAMLSyntaxError_1 = YAMLSyntaxError;
var YAMLWarning_1 = YAMLWarning;

var errors = {
	YAMLError: YAMLError_1,
	YAMLReferenceError: YAMLReferenceError_1,
	YAMLSemanticError: YAMLSemanticError_1,
	YAMLSyntaxError: YAMLSyntaxError_1,
	YAMLWarning: YAMLWarning_1
};

class BlankLine extends Node_1.Node {
  constructor() {
    super(constants.Type.BLANK_LINE);
  }
  /* istanbul ignore next */


  get includesTrailingLines() {
    // This is never called from anywhere, but if it were,
    // this is the value it should return.
    return true;
  }
  /**
   * Parses a blank line from the source
   *
   * @param {ParseContext} context
   * @param {number} start - Index of first \n character
   * @returns {number} - Index of the character after this
   */


  parse(context, start) {
    this.context = context;
    this.range = new Range_1.Range(start, start + 1);
    return start + 1;
  }

}

var BlankLine_2 = BlankLine;

var BlankLine_1 = {
	BlankLine: BlankLine_2
};

class CollectionItem extends Node_1.Node {
  constructor(type, props) {
    super(type, props);
    this.node = null;
  }

  get includesTrailingLines() {
    return !!this.node && this.node.includesTrailingLines;
  }
  /**
   * @param {ParseContext} context
   * @param {number} start - Index of first character
   * @returns {number} - Index of the character after this
   */


  parse(context, start) {
    this.context = context;
    const {
      parseNode,
      src
    } = context;
    let {
      atLineStart,
      lineStart
    } = context;
    if (!atLineStart && this.type === constants.Type.SEQ_ITEM) this.error = new errors.YAMLSemanticError(this, 'Sequence items must not have preceding content on the same line');
    const indent = atLineStart ? start - lineStart : context.indent;
    let offset = Node_1.Node.endOfWhiteSpace(src, start + 1);
    let ch = src[offset];
    const inlineComment = ch === '#';
    const comments = [];
    let blankLine = null;

    while (ch === '\n' || ch === '#') {
      if (ch === '#') {
        const end = Node_1.Node.endOfLine(src, offset + 1);
        comments.push(new Range_1.Range(offset, end));
        offset = end;
      } else {
        atLineStart = true;
        lineStart = offset + 1;
        const wsEnd = Node_1.Node.endOfWhiteSpace(src, lineStart);

        if (src[wsEnd] === '\n' && comments.length === 0) {
          blankLine = new BlankLine_1.BlankLine();
          lineStart = blankLine.parse({
            src
          }, lineStart);
        }

        offset = Node_1.Node.endOfIndent(src, lineStart);
      }

      ch = src[offset];
    }

    if (Node_1.Node.nextNodeIsIndented(ch, offset - (lineStart + indent), this.type !== constants.Type.SEQ_ITEM)) {
      this.node = parseNode({
        atLineStart,
        inCollection: false,
        indent,
        lineStart,
        parent: this
      }, offset);
    } else if (ch && lineStart > start + 1) {
      offset = lineStart - 1;
    }

    if (this.node) {
      if (blankLine) {
        // Only blank lines preceding non-empty nodes are captured. Note that
        // this means that collection item range start indices do not always
        // increase monotonically. -- eemeli/yaml#126
        const items = context.parent.items || context.parent.contents;
        if (items) items.push(blankLine);
      }

      if (comments.length) Array.prototype.push.apply(this.props, comments);
      offset = this.node.range.end;
    } else {
      if (inlineComment) {
        const c = comments[0];
        this.props.push(c);
        offset = c.end;
      } else {
        offset = Node_1.Node.endOfLine(src, start + 1);
      }
    }

    const end = this.node ? this.node.valueRange.end : offset;
    this.valueRange = new Range_1.Range(start, end);
    return offset;
  }

  setOrigRanges(cr, offset) {
    offset = super.setOrigRanges(cr, offset);
    return this.node ? this.node.setOrigRanges(cr, offset) : offset;
  }

  toString() {
    const {
      context: {
        src
      },
      node,
      range,
      value
    } = this;
    if (value != null) return value;
    const str = node ? src.slice(range.start, node.range.start) + String(node) : src.slice(range.start, range.end);
    return Node_1.Node.addStringTerminator(src, range.end, str);
  }

}

var CollectionItem_2 = CollectionItem;

var CollectionItem_1 = {
	CollectionItem: CollectionItem_2
};

class Comment extends Node_1.Node {
  constructor() {
    super(constants.Type.COMMENT);
  }
  /**
   * Parses a comment line from the source
   *
   * @param {ParseContext} context
   * @param {number} start - Index of first character
   * @returns {number} - Index of the character after this scalar
   */


  parse(context, start) {
    this.context = context;
    const offset = this.parseComment(start);
    this.range = new Range_1.Range(start, offset);
    return offset;
  }

}

var Comment_2 = Comment;

var Comment_1 = {
	Comment: Comment_2
};

function grabCollectionEndComments(node) {
  let cnode = node;

  while (cnode instanceof CollectionItem_1.CollectionItem) cnode = cnode.node;

  if (!(cnode instanceof Collection)) return null;
  const len = cnode.items.length;
  let ci = -1;

  for (let i = len - 1; i >= 0; --i) {
    const n = cnode.items[i];

    if (n.type === constants.Type.COMMENT) {
      // Keep sufficiently indented comments with preceding node
      const {
        indent,
        lineStart
      } = n.context;
      if (indent > 0 && n.range.start >= lineStart + indent) break;
      ci = i;
    } else if (n.type === constants.Type.BLANK_LINE) ci = i;else break;
  }

  if (ci === -1) return null;
  const ca = cnode.items.splice(ci, len - ci);
  const prevEnd = ca[0].range.start;

  while (true) {
    cnode.range.end = prevEnd;
    if (cnode.valueRange && cnode.valueRange.end > prevEnd) cnode.valueRange.end = prevEnd;
    if (cnode === node) break;
    cnode = cnode.context.parent;
  }

  return ca;
}
class Collection extends Node_1.Node {
  static nextContentHasIndent(src, offset, indent) {
    const lineStart = Node_1.Node.endOfLine(src, offset) + 1;
    offset = Node_1.Node.endOfWhiteSpace(src, lineStart);
    const ch = src[offset];
    if (!ch) return false;
    if (offset >= lineStart + indent) return true;
    if (ch !== '#' && ch !== '\n') return false;
    return Collection.nextContentHasIndent(src, offset, indent);
  }

  constructor(firstItem) {
    super(firstItem.type === constants.Type.SEQ_ITEM ? constants.Type.SEQ : constants.Type.MAP);

    for (let i = firstItem.props.length - 1; i >= 0; --i) {
      if (firstItem.props[i].start < firstItem.context.lineStart) {
        // props on previous line are assumed by the collection
        this.props = firstItem.props.slice(0, i + 1);
        firstItem.props = firstItem.props.slice(i + 1);
        const itemRange = firstItem.props[0] || firstItem.valueRange;
        firstItem.range.start = itemRange.start;
        break;
      }
    }

    this.items = [firstItem];
    const ec = grabCollectionEndComments(firstItem);
    if (ec) Array.prototype.push.apply(this.items, ec);
  }

  get includesTrailingLines() {
    return this.items.length > 0;
  }
  /**
   * @param {ParseContext} context
   * @param {number} start - Index of first character
   * @returns {number} - Index of the character after this
   */


  parse(context, start) {
    this.context = context;
    const {
      parseNode,
      src
    } = context; // It's easier to recalculate lineStart here rather than tracking down the
    // last context from which to read it -- eemeli/yaml#2

    let lineStart = Node_1.Node.startOfLine(src, start);
    const firstItem = this.items[0]; // First-item context needs to be correct for later comment handling
    // -- eemeli/yaml#17

    firstItem.context.parent = this;
    this.valueRange = Range_1.Range.copy(firstItem.valueRange);
    const indent = firstItem.range.start - firstItem.context.lineStart;
    let offset = start;
    offset = Node_1.Node.normalizeOffset(src, offset);
    let ch = src[offset];
    let atLineStart = Node_1.Node.endOfWhiteSpace(src, lineStart) === offset;
    let prevIncludesTrailingLines = false;

    while (ch) {
      while (ch === '\n' || ch === '#') {
        if (atLineStart && ch === '\n' && !prevIncludesTrailingLines) {
          const blankLine = new BlankLine_1.BlankLine();
          offset = blankLine.parse({
            src
          }, offset);
          this.valueRange.end = offset;

          if (offset >= src.length) {
            ch = null;
            break;
          }

          this.items.push(blankLine);
          offset -= 1; // blankLine.parse() consumes terminal newline
        } else if (ch === '#') {
          if (offset < lineStart + indent && !Collection.nextContentHasIndent(src, offset, indent)) {
            return offset;
          }

          const comment = new Comment_1.Comment();
          offset = comment.parse({
            indent,
            lineStart,
            src
          }, offset);
          this.items.push(comment);
          this.valueRange.end = offset;

          if (offset >= src.length) {
            ch = null;
            break;
          }
        }

        lineStart = offset + 1;
        offset = Node_1.Node.endOfIndent(src, lineStart);

        if (Node_1.Node.atBlank(src, offset)) {
          const wsEnd = Node_1.Node.endOfWhiteSpace(src, offset);
          const next = src[wsEnd];

          if (!next || next === '\n' || next === '#') {
            offset = wsEnd;
          }
        }

        ch = src[offset];
        atLineStart = true;
      }

      if (!ch) {
        break;
      }

      if (offset !== lineStart + indent && (atLineStart || ch !== ':')) {
        if (offset < lineStart + indent) {
          if (lineStart > start) offset = lineStart;
          break;
        } else if (!this.error) {
          const msg = 'All collection items must start at the same column';
          this.error = new errors.YAMLSyntaxError(this, msg);
        }
      }

      if (firstItem.type === constants.Type.SEQ_ITEM) {
        if (ch !== '-') {
          if (lineStart > start) offset = lineStart;
          break;
        }
      } else if (ch === '-' && !this.error) {
        // map key may start with -, as long as it's followed by a non-whitespace char
        const next = src[offset + 1];

        if (!next || next === '\n' || next === '\t' || next === ' ') {
          const msg = 'A collection cannot be both a mapping and a sequence';
          this.error = new errors.YAMLSyntaxError(this, msg);
        }
      }

      const node = parseNode({
        atLineStart,
        inCollection: true,
        indent,
        lineStart,
        parent: this
      }, offset);
      if (!node) return offset; // at next document start

      this.items.push(node);
      this.valueRange.end = node.valueRange.end;
      offset = Node_1.Node.normalizeOffset(src, node.range.end);
      ch = src[offset];
      atLineStart = false;
      prevIncludesTrailingLines = node.includesTrailingLines; // Need to reset lineStart and atLineStart here if preceding node's range
      // has advanced to check the current line's indentation level
      // -- eemeli/yaml#10 & eemeli/yaml#38

      if (ch) {
        let ls = offset - 1;
        let prev = src[ls];

        while (prev === ' ' || prev === '\t') prev = src[--ls];

        if (prev === '\n') {
          lineStart = ls + 1;
          atLineStart = true;
        }
      }

      const ec = grabCollectionEndComments(node);
      if (ec) Array.prototype.push.apply(this.items, ec);
    }

    return offset;
  }

  setOrigRanges(cr, offset) {
    offset = super.setOrigRanges(cr, offset);
    this.items.forEach(node => {
      offset = node.setOrigRanges(cr, offset);
    });
    return offset;
  }

  toString() {
    const {
      context: {
        src
      },
      items,
      range,
      value
    } = this;
    if (value != null) return value;
    let str = src.slice(range.start, items[0].range.start) + String(items[0]);

    for (let i = 1; i < items.length; ++i) {
      const item = items[i];
      const {
        atLineStart,
        indent
      } = item.context;
      if (atLineStart) for (let i = 0; i < indent; ++i) str += ' ';
      str += String(item);
    }

    return Node_1.Node.addStringTerminator(src, range.end, str);
  }

}

var Collection_2 = Collection;
var grabCollectionEndComments_1 = grabCollectionEndComments;

var Collection_1 = {
	Collection: Collection_2,
	grabCollectionEndComments: grabCollectionEndComments_1
};

class Directive extends Node_1.Node {
  constructor() {
    super(constants.Type.DIRECTIVE);
    this.name = null;
  }

  get parameters() {
    const raw = this.rawValue;
    return raw ? raw.trim().split(/[ \t]+/) : [];
  }

  parseName(start) {
    const {
      src
    } = this.context;
    let offset = start;
    let ch = src[offset];

    while (ch && ch !== '\n' && ch !== '\t' && ch !== ' ') ch = src[offset += 1];

    this.name = src.slice(start, offset);
    return offset;
  }

  parseParameters(start) {
    const {
      src
    } = this.context;
    let offset = start;
    let ch = src[offset];

    while (ch && ch !== '\n' && ch !== '#') ch = src[offset += 1];

    this.valueRange = new Range_1.Range(start, offset);
    return offset;
  }

  parse(context, start) {
    this.context = context;
    let offset = this.parseName(start + 1);
    offset = this.parseParameters(offset);
    offset = this.parseComment(offset);
    this.range = new Range_1.Range(start, offset);
    return offset;
  }

}

var Directive_2 = Directive;

var Directive_1 = {
	Directive: Directive_2
};

class Document extends Node_1.Node {
  static startCommentOrEndBlankLine(src, start) {
    const offset = Node_1.Node.endOfWhiteSpace(src, start);
    const ch = src[offset];
    return ch === '#' || ch === '\n' ? offset : start;
  }

  constructor() {
    super(constants.Type.DOCUMENT);
    this.directives = null;
    this.contents = null;
    this.directivesEndMarker = null;
    this.documentEndMarker = null;
  }

  parseDirectives(start) {
    const {
      src
    } = this.context;
    this.directives = [];
    let atLineStart = true;
    let hasDirectives = false;
    let offset = start;

    while (!Node_1.Node.atDocumentBoundary(src, offset, constants.Char.DIRECTIVES_END)) {
      offset = Document.startCommentOrEndBlankLine(src, offset);

      switch (src[offset]) {
        case '\n':
          if (atLineStart) {
            const blankLine = new BlankLine_1.BlankLine();
            offset = blankLine.parse({
              src
            }, offset);

            if (offset < src.length) {
              this.directives.push(blankLine);
            }
          } else {
            offset += 1;
            atLineStart = true;
          }

          break;

        case '#':
          {
            const comment = new Comment_1.Comment();
            offset = comment.parse({
              src
            }, offset);
            this.directives.push(comment);
            atLineStart = false;
          }
          break;

        case '%':
          {
            const directive = new Directive_1.Directive();
            offset = directive.parse({
              parent: this,
              src
            }, offset);
            this.directives.push(directive);
            hasDirectives = true;
            atLineStart = false;
          }
          break;

        default:
          if (hasDirectives) {
            this.error = new errors.YAMLSemanticError(this, 'Missing directives-end indicator line');
          } else if (this.directives.length > 0) {
            this.contents = this.directives;
            this.directives = [];
          }

          return offset;
      }
    }

    if (src[offset]) {
      this.directivesEndMarker = new Range_1.Range(offset, offset + 3);
      return offset + 3;
    }

    if (hasDirectives) {
      this.error = new errors.YAMLSemanticError(this, 'Missing directives-end indicator line');
    } else if (this.directives.length > 0) {
      this.contents = this.directives;
      this.directives = [];
    }

    return offset;
  }

  parseContents(start) {
    const {
      parseNode,
      src
    } = this.context;
    if (!this.contents) this.contents = [];
    let lineStart = start;

    while (src[lineStart - 1] === '-') lineStart -= 1;

    let offset = Node_1.Node.endOfWhiteSpace(src, start);
    let atLineStart = lineStart === start;
    this.valueRange = new Range_1.Range(offset);

    while (!Node_1.Node.atDocumentBoundary(src, offset, constants.Char.DOCUMENT_END)) {
      switch (src[offset]) {
        case '\n':
          if (atLineStart) {
            const blankLine = new BlankLine_1.BlankLine();
            offset = blankLine.parse({
              src
            }, offset);

            if (offset < src.length) {
              this.contents.push(blankLine);
            }
          } else {
            offset += 1;
            atLineStart = true;
          }

          lineStart = offset;
          break;

        case '#':
          {
            const comment = new Comment_1.Comment();
            offset = comment.parse({
              src
            }, offset);
            this.contents.push(comment);
            atLineStart = false;
          }
          break;

        default:
          {
            const iEnd = Node_1.Node.endOfIndent(src, offset);
            const context = {
              atLineStart,
              indent: -1,
              inFlow: false,
              inCollection: false,
              lineStart,
              parent: this
            };
            const node = parseNode(context, iEnd);
            if (!node) return this.valueRange.end = iEnd; // at next document start

            this.contents.push(node);
            offset = node.range.end;
            atLineStart = false;
            const ec = Collection_1.grabCollectionEndComments(node);
            if (ec) Array.prototype.push.apply(this.contents, ec);
          }
      }

      offset = Document.startCommentOrEndBlankLine(src, offset);
    }

    this.valueRange.end = offset;

    if (src[offset]) {
      this.documentEndMarker = new Range_1.Range(offset, offset + 3);
      offset += 3;

      if (src[offset]) {
        offset = Node_1.Node.endOfWhiteSpace(src, offset);

        if (src[offset] === '#') {
          const comment = new Comment_1.Comment();
          offset = comment.parse({
            src
          }, offset);
          this.contents.push(comment);
        }

        switch (src[offset]) {
          case '\n':
            offset += 1;
            break;

          case undefined:
            break;

          default:
            this.error = new errors.YAMLSyntaxError(this, 'Document end marker line cannot have a non-comment suffix');
        }
      }
    }

    return offset;
  }
  /**
   * @param {ParseContext} context
   * @param {number} start - Index of first character
   * @returns {number} - Index of the character after this
   */


  parse(context, start) {
    context.root = this;
    this.context = context;
    const {
      src
    } = context;
    let offset = src.charCodeAt(start) === 0xfeff ? start + 1 : start; // skip BOM

    offset = this.parseDirectives(offset);
    offset = this.parseContents(offset);
    return offset;
  }

  setOrigRanges(cr, offset) {
    offset = super.setOrigRanges(cr, offset);
    this.directives.forEach(node => {
      offset = node.setOrigRanges(cr, offset);
    });
    if (this.directivesEndMarker) offset = this.directivesEndMarker.setOrigRange(cr, offset);
    this.contents.forEach(node => {
      offset = node.setOrigRanges(cr, offset);
    });
    if (this.documentEndMarker) offset = this.documentEndMarker.setOrigRange(cr, offset);
    return offset;
  }

  toString() {
    const {
      contents,
      directives,
      value
    } = this;
    if (value != null) return value;
    let str = directives.join('');

    if (contents.length > 0) {
      if (directives.length > 0 || contents[0].type === constants.Type.COMMENT) str += '---\n';
      str += contents.join('');
    }

    if (str[str.length - 1] !== '\n') str += '\n';
    return str;
  }

}

var Document_2 = Document;

var Document_1 = {
	Document: Document_2
};

function _defineProperty(obj, key, value) {
  if (key in obj) {
    Object.defineProperty(obj, key, {
      value: value,
      enumerable: true,
      configurable: true,
      writable: true
    });
  } else {
    obj[key] = value;
  }

  return obj;
}

var defineProperty = _defineProperty;

var _rollupPluginBabelHelpers = {
	defineProperty: defineProperty
};

class Alias extends Node_1.Node {
  /**
   * Parses an *alias from the source
   *
   * @param {ParseContext} context
   * @param {number} start - Index of first character
   * @returns {number} - Index of the character after this scalar
   */
  parse(context, start) {
    this.context = context;
    const {
      src
    } = context;
    let offset = Node_1.Node.endOfIdentifier(src, start + 1);
    this.valueRange = new Range_1.Range(start + 1, offset);
    offset = Node_1.Node.endOfWhiteSpace(src, offset);
    offset = this.parseComment(offset);
    return offset;
  }

}

var Alias_2 = Alias;

var Alias_1 = {
	Alias: Alias_2
};

const Chomp = {
  CLIP: 'CLIP',
  KEEP: 'KEEP',
  STRIP: 'STRIP'
};
class BlockValue extends Node_1.Node {
  constructor(type, props) {
    super(type, props);
    this.blockIndent = null;
    this.chomping = Chomp.CLIP;
    this.header = null;
  }

  get includesTrailingLines() {
    return this.chomping === Chomp.KEEP;
  }

  get strValue() {
    if (!this.valueRange || !this.context) return null;
    let {
      start,
      end
    } = this.valueRange;
    const {
      indent,
      src
    } = this.context;
    if (this.valueRange.isEmpty()) return '';
    let lastNewLine = null;
    let ch = src[end - 1];

    while (ch === '\n' || ch === '\t' || ch === ' ') {
      end -= 1;

      if (end <= start) {
        if (this.chomping === Chomp.KEEP) break;else return ''; // probably never happens
      }

      if (ch === '\n') lastNewLine = end;
      ch = src[end - 1];
    }

    let keepStart = end + 1;

    if (lastNewLine) {
      if (this.chomping === Chomp.KEEP) {
        keepStart = lastNewLine;
        end = this.valueRange.end;
      } else {
        end = lastNewLine;
      }
    }

    const bi = indent + this.blockIndent;
    const folded = this.type === constants.Type.BLOCK_FOLDED;
    let atStart = true;
    let str = '';
    let sep = '';
    let prevMoreIndented = false;

    for (let i = start; i < end; ++i) {
      for (let j = 0; j < bi; ++j) {
        if (src[i] !== ' ') break;
        i += 1;
      }

      const ch = src[i];

      if (ch === '\n') {
        if (sep === '\n') str += '\n';else sep = '\n';
      } else {
        const lineEnd = Node_1.Node.endOfLine(src, i);
        const line = src.slice(i, lineEnd);
        i = lineEnd;

        if (folded && (ch === ' ' || ch === '\t') && i < keepStart) {
          if (sep === ' ') sep = '\n';else if (!prevMoreIndented && !atStart && sep === '\n') sep = '\n\n';
          str += sep + line; //+ ((lineEnd < end && src[lineEnd]) || '')

          sep = lineEnd < end && src[lineEnd] || '';
          prevMoreIndented = true;
        } else {
          str += sep + line;
          sep = folded && i < keepStart ? ' ' : '\n';
          prevMoreIndented = false;
        }

        if (atStart && line !== '') atStart = false;
      }
    }

    return this.chomping === Chomp.STRIP ? str : str + '\n';
  }

  parseBlockHeader(start) {
    const {
      src
    } = this.context;
    let offset = start + 1;
    let bi = '';

    while (true) {
      const ch = src[offset];

      switch (ch) {
        case '-':
          this.chomping = Chomp.STRIP;
          break;

        case '+':
          this.chomping = Chomp.KEEP;
          break;

        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
          bi += ch;
          break;

        default:
          this.blockIndent = Number(bi) || null;
          this.header = new Range_1.Range(start, offset);
          return offset;
      }

      offset += 1;
    }
  }

  parseBlockValue(start) {
    const {
      indent,
      src
    } = this.context;
    const explicit = !!this.blockIndent;
    let offset = start;
    let valueEnd = start;
    let minBlockIndent = 1;

    for (let ch = src[offset]; ch === '\n'; ch = src[offset]) {
      offset += 1;
      if (Node_1.Node.atDocumentBoundary(src, offset)) break;
      const end = Node_1.Node.endOfBlockIndent(src, indent, offset); // should not include tab?

      if (end === null) break;
      const ch = src[end];
      const lineIndent = end - (offset + indent);

      if (!this.blockIndent) {
        // no explicit block indent, none yet detected
        if (src[end] !== '\n') {
          // first line with non-whitespace content
          if (lineIndent < minBlockIndent) {
            const msg = 'Block scalars with more-indented leading empty lines must use an explicit indentation indicator';
            this.error = new errors.YAMLSemanticError(this, msg);
          }

          this.blockIndent = lineIndent;
        } else if (lineIndent > minBlockIndent) {
          // empty line with more whitespace
          minBlockIndent = lineIndent;
        }
      } else if (ch && ch !== '\n' && lineIndent < this.blockIndent) {
        if (src[end] === '#') break;

        if (!this.error) {
          const src = explicit ? 'explicit indentation indicator' : 'first line';
          const msg = `Block scalars must not be less indented than their ${src}`;
          this.error = new errors.YAMLSemanticError(this, msg);
        }
      }

      if (src[end] === '\n') {
        offset = end;
      } else {
        offset = valueEnd = Node_1.Node.endOfLine(src, end);
      }
    }

    if (this.chomping !== Chomp.KEEP) {
      offset = src[valueEnd] ? valueEnd + 1 : valueEnd;
    }

    this.valueRange = new Range_1.Range(start + 1, offset);
    return offset;
  }
  /**
   * Parses a block value from the source
   *
   * Accepted forms are:
   * ```
   * BS
   * block
   * lines
   *
   * BS #comment
   * block
   * lines
   * ```
   * where the block style BS matches the regexp `[|>][-+1-9]*` and block lines
   * are empty or have an indent level greater than `indent`.
   *
   * @param {ParseContext} context
   * @param {number} start - Index of first character
   * @returns {number} - Index of the character after this block
   */


  parse(context, start) {
    this.context = context;
    const {
      src
    } = context;
    let offset = this.parseBlockHeader(start);
    offset = Node_1.Node.endOfWhiteSpace(src, offset);
    offset = this.parseComment(offset);
    offset = this.parseBlockValue(offset);
    return offset;
  }

  setOrigRanges(cr, offset) {
    offset = super.setOrigRanges(cr, offset);
    return this.header ? this.header.setOrigRange(cr, offset) : offset;
  }

}

var BlockValue_2 = BlockValue;
var Chomp_1 = Chomp;

var BlockValue_1 = {
	BlockValue: BlockValue_2,
	Chomp: Chomp_1
};

class FlowCollection extends Node_1.Node {
  constructor(type, props) {
    super(type, props);
    this.items = null;
  }

  prevNodeIsJsonLike(idx = this.items.length) {
    const node = this.items[idx - 1];
    return !!node && (node.jsonLike || node.type === constants.Type.COMMENT && this.prevNodeIsJsonLike(idx - 1));
  }
  /**
   * @param {ParseContext} context
   * @param {number} start - Index of first character
   * @returns {number} - Index of the character after this
   */


  parse(context, start) {
    this.context = context;
    const {
      parseNode,
      src
    } = context;
    let {
      indent,
      lineStart
    } = context;
    let char = src[start]; // { or [

    this.items = [{
      char,
      offset: start
    }];
    let offset = Node_1.Node.endOfWhiteSpace(src, start + 1);
    char = src[offset];

    while (char && char !== ']' && char !== '}') {
      switch (char) {
        case '\n':
          {
            lineStart = offset + 1;
            const wsEnd = Node_1.Node.endOfWhiteSpace(src, lineStart);

            if (src[wsEnd] === '\n') {
              const blankLine = new BlankLine_1.BlankLine();
              lineStart = blankLine.parse({
                src
              }, lineStart);
              this.items.push(blankLine);
            }

            offset = Node_1.Node.endOfIndent(src, lineStart);

            if (offset <= lineStart + indent) {
              char = src[offset];

              if (offset < lineStart + indent || char !== ']' && char !== '}') {
                const msg = 'Insufficient indentation in flow collection';
                this.error = new errors.YAMLSemanticError(this, msg);
              }
            }
          }
          break;

        case ',':
          {
            this.items.push({
              char,
              offset
            });
            offset += 1;
          }
          break;

        case '#':
          {
            const comment = new Comment_1.Comment();
            offset = comment.parse({
              src
            }, offset);
            this.items.push(comment);
          }
          break;

        case '?':
        case ':':
          {
            const next = src[offset + 1];

            if (next === '\n' || next === '\t' || next === ' ' || next === ',' || // in-flow : after JSON-like key does not need to be followed by whitespace
            char === ':' && this.prevNodeIsJsonLike()) {
              this.items.push({
                char,
                offset
              });
              offset += 1;
              break;
            }
          }
        // fallthrough

        default:
          {
            const node = parseNode({
              atLineStart: false,
              inCollection: false,
              inFlow: true,
              indent: -1,
              lineStart,
              parent: this
            }, offset);

            if (!node) {
              // at next document start
              this.valueRange = new Range_1.Range(start, offset);
              return offset;
            }

            this.items.push(node);
            offset = Node_1.Node.normalizeOffset(src, node.range.end);
          }
      }

      offset = Node_1.Node.endOfWhiteSpace(src, offset);
      char = src[offset];
    }

    this.valueRange = new Range_1.Range(start, offset + 1);

    if (char) {
      this.items.push({
        char,
        offset
      });
      offset = Node_1.Node.endOfWhiteSpace(src, offset + 1);
      offset = this.parseComment(offset);
    }

    return offset;
  }

  setOrigRanges(cr, offset) {
    offset = super.setOrigRanges(cr, offset);
    this.items.forEach(node => {
      if (node instanceof Node_1.Node) {
        offset = node.setOrigRanges(cr, offset);
      } else if (cr.length === 0) {
        node.origOffset = node.offset;
      } else {
        let i = offset;

        while (i < cr.length) {
          if (cr[i] > node.offset) break;else ++i;
        }

        node.origOffset = node.offset + i;
        offset = i;
      }
    });
    return offset;
  }

  toString() {
    const {
      context: {
        src
      },
      items,
      range,
      value
    } = this;
    if (value != null) return value;
    const nodes = items.filter(item => item instanceof Node_1.Node);
    let str = '';
    let prevEnd = range.start;
    nodes.forEach(node => {
      const prefix = src.slice(prevEnd, node.range.start);
      prevEnd = node.range.end;
      str += prefix + String(node);

      if (str[str.length - 1] === '\n' && src[prevEnd - 1] !== '\n' && src[prevEnd] === '\n') {
        // Comment range does not include the terminal newline, but its
        // stringified value does. Without this fix, newlines at comment ends
        // get duplicated.
        prevEnd += 1;
      }
    });
    str += src.slice(prevEnd, range.end);
    return Node_1.Node.addStringTerminator(src, range.end, str);
  }

}

var FlowCollection_2 = FlowCollection;

var FlowCollection_1 = {
	FlowCollection: FlowCollection_2
};

class PlainValue extends Node_1.Node {
  static endOfLine(src, start, inFlow) {
    let ch = src[start];
    let offset = start;

    while (ch && ch !== '\n') {
      if (inFlow && (ch === '[' || ch === ']' || ch === '{' || ch === '}' || ch === ',')) break;
      const next = src[offset + 1];
      if (ch === ':' && (!next || next === '\n' || next === '\t' || next === ' ' || inFlow && next === ',')) break;
      if ((ch === ' ' || ch === '\t') && next === '#') break;
      offset += 1;
      ch = next;
    }

    return offset;
  }

  get strValue() {
    if (!this.valueRange || !this.context) return null;
    let {