Add m-esr52 at 52.6.0

1 files changed, 90 insertions, 0 deletions

diff --git a/js/src/tests/ecma_6/Expressions/ToPropertyKey-symbols.js b/js/src/tests/ecma_6/Expressions/ToPropertyKey-symbols.js
new file mode 100644
index 000000000..32b3994b3
--- /dev/null
+++ b/js/src/tests/ecma_6/Expressions/ToPropertyKey-symbols.js
@@ -0,0 +1,90 @@
+var symbols = [
+    Symbol(), Symbol("iterator"), Symbol.for("iterator"), Symbol.iterator
+];
+
+for (var sym of symbols) {
+    var key = {
+        toString() { return sym; }
+    };
+
+    // Test that ToPropertyKey can return a symbol in each of the following
+    // contexts.
+
+    // Computed property names.
+    var obj = {[key]: 13};
+    var found = Reflect.ownKeys(obj);
+    assertEq(found.length, 1);
+    assertEq(found[0], sym);
+
+    // Computed accessor property names.
+    var obj2 = {
+        get [key]() { return "got"; },
+        set [key](v) { this.v = v; }
+    };
+    assertEq(obj2[sym], "got");
+    obj2[sym] = 33;
+    assertEq(obj2.v, 33);
+
+    // Getting and setting properties.
+    assertEq(obj[key], 13);
+    obj[key] = 19;
+    assertEq(obj[sym], 19);
+    (function () { "use strict"; obj[key] = 20; })();
+    assertEq(obj[sym], 20);
+    obj[key]++;
+    assertEq(obj[sym], 21);
+
+    // Getting properties of primitive values.
+    Number.prototype[sym] = "success";
+    assertEq(Math.PI[key], "success");
+    delete Number.prototype[sym];
+
+    // Getting a super property.
+    class X {
+        [sym]() { return "X"; }
+    }
+    class Y extends X {
+        [sym]() { return super[key]() + "Y"; }
+    }
+    var y = new Y();
+    assertEq(y[sym](), "XY");
+
+    // Setting a super property.
+    class Z {
+        set [sym](v) {
+            this.self = this;
+            this.value = v;
+        }
+    }
+    class W extends Z {
+        set [sym](v) {
+            this.isW = true;
+            super[key] = v;
+        }
+    }
+    var w = new W();
+    w[key] = "ok";
+    assertEq(w.self, w);
+    assertEq(w.value, "ok");
+    assertEq(w.isW, true);
+
+    // Deleting properties.
+    obj = {[sym]: 1};
+    assertEq(delete obj[key], true);
+    assertEq(sym in obj, false);
+
+    // LHS of `in` expressions.
+    assertEq(key in {iterator: 0}, false);
+    assertEq(key in {[sym]: 0}, true);
+
+    // Methods of Object and Object.prototype
+    obj = {};
+    Object.defineProperty(obj, key, {value: "ok", enumerable: true});
+    assertEq(obj[sym], "ok");
+    assertEq(obj.hasOwnProperty(key), true);
+    assertEq(obj.propertyIsEnumerable(key), true);
+    var desc = Object.getOwnPropertyDescriptor(obj, key);
+    assertEq(desc.value, "ok");
+}
+
+reportCompare(0, 0);