1 files changed, 49 insertions, 0 deletions
diff --git a/js/src/builtin/WeakMap.js b/js/src/builtin/WeakMap.js
new file mode 100644
index 000000000..066a72bfe
--- /dev/null
+++ b/js/src/builtin/WeakMap.js
@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// ES2017 draft rev 0e10c9f29fca1385980c08a7d5e7bb3eb775e2e4
+// 23.3.1.1 WeakMap, steps 6-8
+function WeakMapConstructorInit(iterable) {
+    var map = this;
+
+    // Step 6.a.
+    var adder = map.set;
+
+    // Step 6.b.
+    if (!IsCallable(adder))
+        ThrowTypeError(JSMSG_NOT_FUNCTION, typeof adder);
+
+    // Step 6.c.
+    var iterFn = iterable[std_iterator];
+    if (!IsCallable(iterFn))
+        ThrowTypeError(JSMSG_NOT_ITERABLE, DecompileArg(0, iterable));
+
+    var iter = callContentFunction(iterFn, iterable);
+    if (!IsObject(iter))
+        ThrowTypeError(JSMSG_NOT_NONNULL_OBJECT, typeof iter);
+
+    // Step 7 (not applicable).
+
+    // Step 8.
+    while (true) {
+        // Step 8.a.
+        var next = callContentFunction(iter.next, iter);
+        if (!IsObject(next))
+            ThrowTypeError(JSMSG_NOT_NONNULL_OBJECT, typeof next);
+
+        // Step 8.b.
+        if (next.done)
+            return;
+
+        // Step 8.c.
+        var nextItem = next.value;
+
+        // Step 8.d.
+        if (!IsObject(nextItem))
+            ThrowTypeError(JSMSG_INVALID_MAP_ITERABLE, "WeakMap");
+
+        // Steps 8.e-j.
+        callContentFunction(adder, map, nextItem[0], nextItem[1]);
+    }
+}