eslint-plugin-lob/lib/rules/padded-describes.js

Custom ESLint rules for Lob repositories

'use strict';

var ERROR_MESSAGE = 'Missing new line at the {{position}} of a describe block.';

function isFunctionExpression (nodeType) {
  return nodeType === 'FunctionExpression' || nodeType === 'ArrowFunctionExpression';
}

function isDescribeBlock (node) {
  return isFunctionExpression(node.parent.type) &&
    node.parent.parent.type === 'CallExpression' &&
    node.parent.parent.callee.name === 'describe';
}

function isLocatedBefore (a, b) {
  return a.range[1] < b.range[0];
}

module.exports = {
  meta: {
    type: 'layout',
    schema: []
  },
  create (ctx) {
    var sourceCode = ctx.sourceCode;

    function isBlockTopPadded (node) {
      var blockStart = node.loc.start.line;
      var first = node.body[0];
      var expectedFirstLine = blockStart + 2;
      var leadingComments = (sourceCode.getCommentsBefore ? sourceCode.getCommentsBefore(first) : first.leadingComments || []).slice();
      var firstLine = first.loc.start.line;

      while (leadingComments.length > 0 && leadingComments[0].loc.start.line <= node.loc.start.line) {
        leadingComments.shift();
      }

      var firstComment = leadingComments[0];

      if (firstComment && isLocatedBefore(firstComment, first)) {
        firstLine = firstComment.loc.start.line;
      }

      return expectedFirstLine <= firstLine;
    }

    function isBlockBottomPadded (node) {
      var blockEnd = node.loc.end.line;
      var last = node.body[node.body.length - 1];
      var lastToken = sourceCode.getLastToken(last);
      var expectedLastLine = blockEnd - 2;
      var trailingComments = (sourceCode.getCommentsAfter ? sourceCode.getCommentsAfter(last) : last.trailingComments || []).slice();
      var lastLine = lastToken.loc.end.line;

      while (trailingComments.length > 0 && trailingComments[trailingComments.length - 1].loc.end.line >= node.loc.end.line) {
        trailingComments.pop();
      }

      var lastComment = trailingComments[trailingComments.length - 1];

      if (lastComment && isLocatedBefore(lastToken, lastComment)) {
        lastLine = lastComment.loc.end.line;
      }

      return lastLine <= expectedLastLine;
    }

    return {
      BlockStatement (node) {
        if (node.body.length > 0 && isDescribeBlock(node)) {
          var blockHasTopPadding = isBlockTopPadded(node);
          var blockHasBottomPadding = isBlockBottomPadded(node);

          if (!blockHasTopPadding) {
            ctx.report({ node, message: ERROR_MESSAGE, data: { position: 'top' } });
          }

          if (!blockHasBottomPadding) {
            var loc = { line: node.loc.end.line, column: node.loc.end.column - 1 };

            ctx.report({ node, loc, message: ERROR_MESSAGE, data: { position: 'bottom' } });
          }
        }
      }
    };
  }
};