implemented frontend including separate message system; started to implement backend

yjs-poll/node_modules/lib0/dist/patience.cjs

@@ -0,0 +1,236 @@
+'use strict';
+
+Object.defineProperty(exports, '__esModule', { value: true });
+
+var map = require('./map-24d263c0.cjs');
+var math = require('./math-96d5e8c4.cjs');
+var array = require('./array-78849c95.cjs');
+require('./set-5b47859e.cjs');
+
+/**
+ * A very simple diff algorithm. Slightly adapted to support splitting at different stages (e.g.
+ * first diff lines, then diff words)
+ *
+ * https://bramcohen.livejournal.com/73318.html
+ *
+ * @experiemantal This API will likely change.
+ */
+
+/**
+ * Implementation of patience diff. Expects that content is pre-split (e.g. by newline).
+ *
+ * @param {Array<string>} as
+ * @param {Array<string>} bs
+ * @return {Array<{ index: number, remove: Array<string>, insert: Array<string>}>} changeset @todo should use delta instead
+ */
+const diff = (as, bs) => {
+  const {
+    middleAs,
+    middleBs,
+    commonPrefix
+  } = removeCommonPrefixAndSuffix(as, bs);
+  return lcs(middleAs, middleBs, commonPrefix)
+};
+
+/**
+ * @param {string} a
+ * @param {string} b
+ * @param {RegExp|string} _regexp
+ */
+const diffSplitBy = (a, b, _regexp) => {
+  const isStringSeparator = typeof _regexp === 'string';
+  const separator = isStringSeparator ? _regexp : '';
+  const regexp = isStringSeparator ? new RegExp(_regexp, 'g') : _regexp;
+  const as = splitByRegexp(a, regexp, !isStringSeparator);
+  const bs = splitByRegexp(b, regexp, !isStringSeparator);
+  const changes = diff(as, bs);
+  let prevSplitIndex = 0;
+  let prevStringIndex = 0;
+  return changes.map(change => {
+    for (; prevSplitIndex < change.index; prevSplitIndex++) {
+      prevStringIndex += as[prevSplitIndex].length;
+    }
+    return {
+      index: prevStringIndex,
+      remove: change.remove.join(separator),
+      insert: change.insert.join(separator)
+    }
+  })
+};
+
+/**
+ * Sensible default for diffing strings using patience (it's fast though).
+ *
+ * Perform different types of patience diff on the content. Diff first by newline, then paragraphs, then by word
+ * (split by space, brackets, punctuation)
+ *
+ * @param {string} a
+ * @param {string} b
+ */
+const diffAuto = (a, b) =>
+  diffSplitBy(a, b, '\n').map(d =>
+    diffSplitBy(d.remove, d.insert, /\. |[a-zA-Z0-9]+|[. ()[\],;{}]/g).map(dd => ({
+      insert: dd.insert,
+      remove: dd.remove,
+      index: dd.index + d.index
+    }))
+  ).flat();
+
+/**
+ * @param {Array<string>} as
+ * @param {Array<string>} bs
+ */
+const removeCommonPrefixAndSuffix = (as, bs) => {
+  const commonLen = math.min(as.length, bs.length);
+  let commonPrefix = 0;
+  let commonSuffix = 0;
+  // match start
+  for (; commonPrefix < commonLen && as[commonPrefix] === bs[commonPrefix]; commonPrefix++) { /* nop */ }
+  // match end
+  for (; commonSuffix < commonLen - commonPrefix && as[as.length - 1 - commonSuffix] === bs[bs.length - 1 - commonSuffix]; commonSuffix++) { /* nop */ }
+  const middleAs = as.slice(commonPrefix, as.length - commonSuffix);
+  const middleBs = bs.slice(commonPrefix, bs.length - commonSuffix);
+  return {
+    middleAs, middleBs, commonPrefix, commonSuffix
+  }
+};
+
+/**
+ * Splits string by regex and returns all strings as an array. The matched parts are also returned.
+ *
+ * @param {string} str
+ * @param {RegExp} regexp
+ * @param {boolean} includeSeparator
+ */
+const splitByRegexp = (str, regexp, includeSeparator) => {
+  const matches = [...str.matchAll(regexp)];
+  let prevIndex = 0;
+  /**
+   * @type {Array<string>}
+   */
+  const res = [];
+  matches.forEach(m => {
+    prevIndex < (m.index || 0) && res.push(str.slice(prevIndex, m.index));
+    includeSeparator && res.push(m[0]); // is always non-empty
+    prevIndex = /** @type {number} */ (m.index) + m[0].length;
+  });
+  const end = str.slice(prevIndex);
+  end.length > 0 && res.push(end);
+  return res
+};
+
+/**
+ * An item may have multiple occurances (not when matching unique entries). It also may have a
+ * reference to the stack of other items (from as to bs).
+ */
+class Item {
+  constructor () {
+    /**
+     * @type {Array<number>}
+     */
+    this.indexes = [];
+    /**
+     * The matching item from the other side
+     * @type {Item?}
+     */
+    this.match = null;
+    /**
+     * For patience sort. Reference (index of the stack) to the previous pile.
+     *
+     * @type {Item?}
+     */
+    this.ref = null;
+  }
+}
+
+/**
+ * @param {Array<string>} xs
+ */
+const partition = xs => {
+  /**
+   * @type {Map<string,Item>}
+   */
+  const refs = map.create();
+  xs.forEach((x, index) => {
+    map.setIfUndefined(refs, x, () => new Item()).indexes.push(index);
+  });
+  return refs
+};
+
+/**
+ * Find the longest common subsequence of items using patience sort.
+ *
+ * @param {Array<string>} as
+ * @param {Array<string>} bs
+ * @param {number} indexAdjust
+ */
+const lcs = (as, bs, indexAdjust) => {
+  if (as.length === 0 && bs.length === 0) return []
+  const aParts = partition(as);
+  const bParts = partition(bs);
+  /**
+   * @type {Array<Array<Item>>} I.e. Array<Pile<Item>>
+   */
+  const piles = [];
+  aParts.forEach((aItem, aKey) => {
+    // skip if no match or if either item is not unique
+    if (aItem.indexes.length > 1 || (aItem.match = bParts.get(aKey) || null) == null || aItem.match.indexes.length > 1) return
+    for (let i = 0; i < piles.length; i++) {
+      const pile = piles[i];
+      if (aItem.match.indexes[0] < /** @type {Item} */ (pile[pile.length - 1].match).indexes[0]) {
+        pile.push(aItem);
+        if (i > 0) aItem.ref = array.last(piles[i - 1]);
+        return
+      }
+    }
+    piles.length > 0 && (aItem.ref = array.last(piles[piles.length - 1]));
+    piles.push([aItem]);
+  });
+  /**
+   * References to all matched items
+   *
+   * @type {Array<Item>}
+   */
+  const matches = [];
+  /**
+   * @type {Item?}
+   */
+  let currPileItem = piles[piles.length - 1]?.[0];
+  while (currPileItem != null) {
+    matches.push(currPileItem);
+    currPileItem = currPileItem.ref;
+  }
+  matches.reverse();
+  // add pseude match (assume the string terminal always matches)
+  const pseudoA = new Item();
+  const pseudoB = new Item();
+  pseudoA.match = pseudoB;
+  pseudoA.indexes.push(as.length);
+  pseudoB.indexes.push(bs.length);
+  matches.push(pseudoA);
+  /**
+   * @type {Array<{ index: number, remove: Array<string>, insert: Array<string>}>}
+   */
+  const changeset = [];
+  let diffAStart = 0;
+  let diffBStart = 0;
+  for (let i = 0; i < matches.length; i++) {
+    const m = matches[i];
+    const delLength = m.indexes[0] - diffAStart;
+    const insLength = /** @type {Item} */ (m.match).indexes[0] - diffBStart;
+    if (delLength !== 0 || insLength !== 0) {
+      const stripped = removeCommonPrefixAndSuffix(as.slice(diffAStart, diffAStart + delLength), bs.slice(diffBStart, diffBStart + insLength));
+      if (stripped.middleAs.length !== 0 || stripped.middleBs.length !== 0) {
+        changeset.push({ index: diffAStart + indexAdjust + stripped.commonPrefix, remove: stripped.middleAs, insert: stripped.middleBs });
+      }
+    }
+    diffAStart = m.indexes[0] + 1;
+    diffBStart = /** @type {Item} */ (m.match).indexes[0] + 1;
+  }
+  return changeset
+};
+
+exports.diff = diff;
+exports.diffAuto = diffAuto;
+exports.diffSplitBy = diffSplitBy;
+//# sourceMappingURL=patience.cjs.map