add node_modules to address #4364

1 files changed, 66 insertions, 0 deletions

diff --git a/node_modules/asap/browser-asap.js b/node_modules/asap/browser-asap.js
new file mode 100644
index 000000000..805c98246
--- /dev/null
+++ b/node_modules/asap/browser-asap.js
@@ -0,0 +1,66 @@
+"use strict";
+
+// rawAsap provides everything we need except exception management.
+var rawAsap = require("./raw");
+// RawTasks are recycled to reduce GC churn.
+var freeTasks = [];
+// We queue errors to ensure they are thrown in right order (FIFO).
+// Array-as-queue is good enough here, since we are just dealing with exceptions.
+var pendingErrors = [];
+var requestErrorThrow = rawAsap.makeRequestCallFromTimer(throwFirstError);
+
+function throwFirstError() {
+    if (pendingErrors.length) {
+        throw pendingErrors.shift();
+    }
+}
+
+/**
+ * Calls a task as soon as possible after returning, in its own event, with priority
+ * over other events like animation, reflow, and repaint. An error thrown from an
+ * event will not interrupt, nor even substantially slow down the processing of
+ * other events, but will be rather postponed to a lower priority event.
+ * @param {{call}} task A callable object, typically a function that takes no
+ * arguments.
+ */
+module.exports = asap;
+function asap(task) {
+    var rawTask;
+    if (freeTasks.length) {
+        rawTask = freeTasks.pop();
+    } else {
+        rawTask = new RawTask();
+    }
+    rawTask.task = task;
+    rawAsap(rawTask);
+}
+
+// We wrap tasks with recyclable task objects.  A task object implements
+// `call`, just like a function.
+function RawTask() {
+    this.task = null;
+}
+
+// The sole purpose of wrapping the task is to catch the exception and recycle
+// the task object after its single use.
+RawTask.prototype.call = function () {
+    try {
+        this.task.call();
+    } catch (error) {
+        if (asap.onerror) {
+            // This hook exists purely for testing purposes.
+            // Its name will be periodically randomized to break any code that
+            // depends on its existence.
+            asap.onerror(error);
+        } else {
+            // In a web browser, exceptions are not fatal. However, to avoid
+            // slowing down the queue of pending tasks, we rethrow the error in a
+            // lower priority turn.
+            pendingErrors.push(error);
+            requestErrorThrow();
+        }
+    } finally {
+        this.task = null;
+        freeTasks[freeTasks.length] = this;
+    }
+};