1 files changed, 198 insertions, 0 deletions
diff --git a/node_modules/jsdom/lib/jsdom/living/helpers/mutation-observers.js b/node_modules/jsdom/lib/jsdom/living/helpers/mutation-observers.js
new file mode 100644
index 0000000..c1c9209
--- /dev/null
+++ b/node_modules/jsdom/lib/jsdom/living/helpers/mutation-observers.js
@@ -0,0 +1,198 @@
+"use strict";
+
+const { domSymbolTree } = require("./internal-constants");
+const reportException = require("./runtime-script-errors");
+
+const Event = require("../generated/Event");
+const idlUtils = require("../generated/utils");
+const MutationRecord = require("../generated/MutationRecord");
+
+const MUTATION_TYPE = {
+  ATTRIBUTES: "attributes",
+  CHARACTER_DATA: "characterData",
+  CHILD_LIST: "childList"
+};
+
+// Note:
+// Since jsdom doesn't currently implement the concept of "unit of related similar-origin browsing contexts"
+// (https://html.spec.whatwg.org/multipage/browsers.html#unit-of-related-similar-origin-browsing-contexts)
+// we will approximate that the following properties are global for now.
+
+// https://dom.spec.whatwg.org/#mutation-observer-compound-microtask-queued-flag
+let mutationObserverMicrotaskQueueFlag = false;
+
+// Non-spec compliant: List of all the mutation observers with mutation records enqueued. It's a replacement for
+// mutation observer list (https://dom.spec.whatwg.org/#mutation-observer-list) but without leaking since it's empty
+// before notifying the mutation observers.
+const activeMutationObservers = new Set();
+
+// https://dom.spec.whatwg.org/#signal-slot-list
+const signalSlotList = [];
+
+// https://dom.spec.whatwg.org/#queue-a-mutation-record
+function queueMutationRecord(
+  type,
+  target,
+  name,
+  namespace,
+  oldValue,
+  addedNodes,
+  removedNodes,
+  previousSibling,
+  nextSibling
+) {
+  const interestedObservers = new Map();
+
+  const nodes = domSymbolTree.ancestorsToArray(target);
+
+  for (const node of nodes) {
+    for (const registered of node._registeredObserverList) {
+      const { options, observer: mo } = registered;
+
+      if (
+        !(node !== target && options.subtree === false) &&
+        !(type === MUTATION_TYPE.ATTRIBUTES && options.attributes !== true) &&
+        !(type === MUTATION_TYPE.ATTRIBUTES && options.attributeFilter &&
+          !options.attributeFilter.some(value => value === name || value === namespace)) &&
+        !(type === MUTATION_TYPE.CHARACTER_DATA && options.characterData !== true) &&
+        !(type === MUTATION_TYPE.CHILD_LIST && options.childList === false)
+      ) {
+        if (!interestedObservers.has(mo)) {
+          interestedObservers.set(mo, null);
+        }
+
+        if (
+          (type === MUTATION_TYPE.ATTRIBUTES && options.attributeOldValue === true) ||
+          (type === MUTATION_TYPE.CHARACTER_DATA && options.characterDataOldValue === true)
+        ) {
+          interestedObservers.set(mo, oldValue);
+        }
+      }
+    }
+  }
+
+  for (const [observer, mappedOldValue] of interestedObservers.entries()) {
+    const record = MutationRecord.createImpl(target._globalObject, [], {
+      type,
+      target,
+      attributeName: name,
+      attributeNamespace: namespace,
+      oldValue: mappedOldValue,
+      addedNodes,
+      removedNodes,
+      previousSibling,
+      nextSibling
+    });
+
+    observer._recordQueue.push(record);
+    activeMutationObservers.add(observer);
+  }
+
+  queueMutationObserverMicrotask();
+}
+
+// https://dom.spec.whatwg.org/#queue-a-tree-mutation-record
+function queueTreeMutationRecord(target, addedNodes, removedNodes, previousSibling, nextSibling) {
+  queueMutationRecord(
+    MUTATION_TYPE.CHILD_LIST,
+    target,
+    null,
+    null,
+    null,
+    addedNodes,
+    removedNodes,
+    previousSibling,
+    nextSibling
+  );
+}
+
+// https://dom.spec.whatwg.org/#queue-an-attribute-mutation-record
+function queueAttributeMutationRecord(target, name, namespace, oldValue) {
+  queueMutationRecord(
+    MUTATION_TYPE.ATTRIBUTES,
+    target,
+    name,
+    namespace,
+    oldValue,
+    [],
+    [],
+    null,
+    null
+  );
+}
+
+// https://dom.spec.whatwg.org/#queue-a-mutation-observer-compound-microtask
+function queueMutationObserverMicrotask() {
+  if (mutationObserverMicrotaskQueueFlag) {
+    return;
+  }
+
+  mutationObserverMicrotaskQueueFlag = true;
+
+  Promise.resolve().then(() => {
+    notifyMutationObservers();
+  });
+}
+
+// https://dom.spec.whatwg.org/#notify-mutation-observers
+function notifyMutationObservers() {
+  mutationObserverMicrotaskQueueFlag = false;
+
+  const notifyList = [...activeMutationObservers].sort((a, b) => a._id - b._id);
+  activeMutationObservers.clear();
+
+  const signalList = [...signalSlotList];
+  signalSlotList.splice(0, signalSlotList.length);
+
+  for (const mo of notifyList) {
+    const records = [...mo._recordQueue];
+    mo._recordQueue = [];
+
+    for (const node of mo._nodeList) {
+      node._registeredObserverList = node._registeredObserverList.filter(registeredObserver => {
+        return registeredObserver.source !== mo;
+      });
+    }
+
+    if (records.length > 0) {
+      try {
+        const moWrapper = idlUtils.wrapperForImpl(mo);
+        mo._callback.call(
+          moWrapper,
+          records.map(idlUtils.wrapperForImpl),
+          moWrapper
+        );
+      } catch (e) {
+        const { target } = records[0];
+        const window = target._ownerDocument._defaultView;
+
+        reportException(window, e);
+      }
+    }
+  }
+
+  for (const slot of signalList) {
+    const slotChangeEvent = Event.createImpl(
+      slot._globalObject,
+      [
+        "slotchange",
+        { bubbles: true }
+      ],
+      { isTrusted: true }
+    );
+
+    slot._dispatch(slotChangeEvent);
+  }
+}
+
+module.exports = {
+  MUTATION_TYPE,
+
+  queueMutationRecord,
+  queueTreeMutationRecord,
+  queueAttributeMutationRecord,
+
+  queueMutationObserverMicrotask,
+
+  signalSlotList
+};