1 files changed, 76 insertions, 0 deletions
diff --git a/op_crates/web/02_abort_signal.js b/op_crates/web/02_abort_signal.js
new file mode 100644
index 000000000..908e85ac9
--- /dev/null
+++ b/op_crates/web/02_abort_signal.js
@@ -0,0 +1,76 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+((window) => {
+  const add = Symbol("add");
+  const signalAbort = Symbol("signalAbort");
+  const remove = Symbol("remove");
+
+  class AbortSignal extends EventTarget {
+    #aborted = false;
+    #abortAlgorithms = new Set();
+
+    [add](algorithm) {
+      this.#abortAlgorithms.add(algorithm);
+    }
+
+    [signalAbort]() {
+      if (this.#aborted) {
+        return;
+      }
+      this.#aborted = true;
+      for (const algorithm of this.#abortAlgorithms) {
+        algorithm();
+      }
+      this.#abortAlgorithms.clear();
+      this.dispatchEvent(new Event("abort"));
+    }
+
+    [remove](algorithm) {
+      this.#abortAlgorithms.delete(algorithm);
+    }
+
+    constructor() {
+      super();
+      this.onabort = null;
+      this.addEventListener("abort", (evt) => {
+        const { onabort } = this;
+        if (typeof onabort === "function") {
+          onabort.call(this, evt);
+        }
+      });
+    }
+
+    get aborted() {
+      return Boolean(this.#aborted);
+    }
+
+    get [Symbol.toStringTag]() {
+      return "AbortSignal";
+    }
+  }
+
+  class AbortController {
+    #signal = new AbortSignal();
+
+    get signal() {
+      return this.#signal;
+    }
+
+    abort() {
+      this.#signal[signalAbort]();
+    }
+
+    get [Symbol.toStringTag]() {
+      return "AbortController";
+    }
+  }
+
+  window.AbortSignal = AbortSignal;
+  window.AbortController = AbortController;
+  window.__bootstrap = window.__bootstrap || {};
+  window.__bootstrap.abortSignal = {
+    add,
+    signalAbort,
+    remove,
+  };
+})(this);