@atlaskit/editor-plugin-show-diff/dist/es2019/pm-plugins/calculateDiff/encodeCharacterWithMarks.js

ShowDiff plugin for @atlaskit/editor-core

/** U+0000 cannot occur in ProseMirror text content, so a token can never be ambiguous. */
const MARK_KEY_SEPARATOR = '\u0000';
const buildMarkKey = marks => marks.map(mark => {
  var _mark$attrs;
  const attrs = (_mark$attrs = mark.attrs) !== null && _mark$attrs !== void 0 ? _mark$attrs : {};
  const attrParts = Object.keys(attrs).sort().map(key => {
    var _attrs$key;
    return `${key}=${JSON.stringify((_attrs$key = attrs[key]) !== null && _attrs$key !== void 0 ? _attrs$key : null)}`;
  });
  return attrParts.length > 0 ? `${mark.type.name}(${attrParts.join(',')})` : mark.type.name;
}).sort().join('&');

/**
 * Keyed on array identity: `prosemirror-changeset` passes the same `child.marks` reference for
 * every character in a text node, so this collapses the key building to once per node.
 */
const markKeyCache = new WeakMap();

/**
 * Folds a character's marks into its `prosemirror-changeset` token. The library default returns
 * only the char code, so marked and unmarked text tokenise identically and a formatting-only edit
 * is invisible to the changeset.
 *
 * Marks and attrs are sorted so the token is order-independent.
 */
export const encodeCharacterWithMarks = (char, marks) => {
  if (marks.length === 0) {
    return char;
  }
  let markKey = markKeyCache.get(marks);
  if (markKey === undefined) {
    markKey = buildMarkKey(marks);
    markKeyCache.set(marks, markKey);
  }
  return `${char}${MARK_KEY_SEPARATOR}${markKey}`;
};