@atlaskit/editor-plugin-show-diff/dist/esm/pm-plugins/utils/charsByOffset.js

ShowDiff plugin for @atlaskit/editor-core

/**
 * Whitespace as the diff treats it, U+00A0 included: a non-breaking space separates words for every
 * consumer here, so it is not a character a change can be said to start on.
 *
 * A Set rather than a regex, to avoid both the `require-unicode-regexp` lint rule and the TS1501
 * error the `u` flag triggers under this package's declaration build target.
 */
var WHITESPACE_CHAR_SET = new Set([' ', '\t', '\n', '\r', '\f', '\v', "\xA0"]);
export var isWhitespaceChar = function isWhitespaceChar(char) {
  return WHITESPACE_CHAR_SET.has(char);
};

/**
 * Build a per-content-offset view of a textblock's characters.
 *
 * Returns an array whose length is `parent.content.size`. For every offset that lies inside a text
 * node, `chars[offset]` is the character at that offset; for every offset that lies inside (or on
 * the edge of) a non-text inline node — hardBreak, mention, emoji, date, … — the entry is `null`,
 * which acts as an *opaque single token*: it counts as one word and is never whitespace.
 *
 * Using doc positions to index `parent.textContent` is wrong because `textContent` strips non-text
 * inline nodes, so every such node shifts the lookup off by its size. This per-offset view restores
 * a 1:1 mapping between doc positions inside the textblock and the character (or "no character",
 * i.e. a hard word boundary) at that position.
 */
export var buildCharsByOffset = function buildCharsByOffset(parent) {
  var chars = new Array(parent.content.size).fill(null);
  parent.content.forEach(function (child, offset) {
    var _child$text;
    if (!child.isText) {
      return;
    }
    var text = (_child$text = child.text) !== null && _child$text !== void 0 ? _child$text : '';
    for (var i = 0; i < text.length; i++) {
      chars[offset + i] = text[i];
    }
  });
  return chars;
};