rsuite-theme/_node_modules/mdast-util-compact/index.js

The suite theme for pagurian

'use strict';

/* Dependencies. */
var visit = require('unist-util-visit');
var modify = require('unist-util-modify-children');

/* Expose. */
module.exports = compact;

/* Make an MDAST tree compact by merging adjacent text
 * nodes. */
function compact(tree, commonmark) {
  var modifier = modify(iterator);

  visit(tree, visitor);

  return tree;

  function visitor(node) {
    if (node.children) {
      modifier(node);
    }
  }

  function iterator(child, index, parent) {
    var siblings = parent.children;
    var prev = index && siblings[index - 1];

    if (
      prev &&
      child.type === prev.type &&
      mergeable(prev, commonmark) &&
      mergeable(child, commonmark)
    ) {
      if (child.value) {
        prev.value += child.value;
      }

      if (child.children) {
        prev.children = prev.children.concat(child.children);
      }

      siblings.splice(index, 1);

      if (prev.position && child.position) {
        prev.position.end = child.position.end;
      }

      return index;
    }
  }
}

function mergeable(node, commonmark) {
  var start;
  var end;

  if (node.type === 'text') {
    if (!node.position) {
      return true;
    }

    start = node.position.start;
    end = node.position.end;

    /* Only merge nodes which occupy the same size as their `value`. */
    return start.line !== end.line ||
      end.column - start.column === node.value.length;
  }

  return commonmark && node.type === 'blockquote';
}