Function makeChange

static/editor.md/lib/codemirror/lib/codemirror.js:4179–4199

(doc, change, ignoreReadOnly)

  // Apply a change to a document, and add it to the document's
  // history, and propagating it to all linked documents.
  function makeChange(doc, change, ignoreReadOnly) {
    if (doc.cm) {
      if (!doc.cm.curOp) return operation(doc.cm, makeChange)(doc, change, ignoreReadOnly);
      if (doc.cm.state.suppressEdits) return;
    }

    if (hasHandler(doc, "beforeChange") || doc.cm && hasHandler(doc.cm, "beforeChange")) {
      change = filterChange(doc, change, true);
      if (!change) return;
    }

    // Possibly split or suppress the update based on the presence
    // of read-only spans in its range.
    var split = sawReadOnlySpans && !ignoreReadOnly && removeReadOnlyRanges(doc, change.from, change.to);
    if (split) {
      for (var i = split.length - 1; i >= 0; --i)
        makeChangeInner(doc, {from: split[i].from, to: split[i].to, text: i ? [""] : change.text});
    } else {
      makeChangeInner(doc, change);
    }
  }

  function makeChangeInner(doc, change) {
    if (change.text.length == 1 && change.text[0] == "" && cmp(change.from, change.to) == 0) return;