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// String.prototype[@@iterator] and StringIterator.prototype surface tests
load(libdir + "array-compare.js");
load(libdir + "asserts.js");
load(libdir + "iteration.js");
function assertDataDescriptor(actual, expected) {
assertEq(actual.value, expected.value);
assertEq(actual.writable, expected.writable);
assertEq(actual.enumerable, expected.enumerable);
assertEq(actual.configurable, expected.configurable);
}
function isConstructor(o) {
try {
new (new Proxy(o, {construct: () => ({})}));
return true;
} catch(e) {
return false;
}
}
function assertBuiltinFunction(o, name, arity) {
var fn = o[name];
assertDataDescriptor(Object.getOwnPropertyDescriptor(o, name), {
value: fn,
writable: true,
enumerable: false,
configurable: true,
});
assertEq(typeof fn, "function");
assertEq(Object.getPrototypeOf(fn), Function.prototype);
assertEq(isConstructor(fn), false);
assertEq(arraysEqual(Object.getOwnPropertyNames(fn).sort(), ["length", "name"].sort()), true);
assertDataDescriptor(Object.getOwnPropertyDescriptor(fn, "length"), {
value: arity,
writable: false,
enumerable: false,
configurable: true
});
var functionName = typeof name === "symbol"
? String(name).replace(/^Symbol\((.+)\)$/, "[$1]")
: name;
assertDataDescriptor(Object.getOwnPropertyDescriptor(fn, "name"), {
value: functionName,
writable: false,
enumerable: false,
configurable: true
});
}
// String.prototype[@@iterator] is a built-in function
assertBuiltinFunction(String.prototype, Symbol.iterator, 0);
// Test StringIterator.prototype surface
var iter = ""[Symbol.iterator]();
var iterProto = Object.getPrototypeOf(iter);
// StringIterator.prototype inherits from %IteratorPrototype%. Check it's the
// same object as %ArrayIteratorPrototype%'s proto.
assertEq(Object.getPrototypeOf(iterProto),
Object.getPrototypeOf(Object.getPrototypeOf([][Symbol.iterator]())));
// Own properties for StringIterator.prototype: "next"
assertEq(arraysEqual(Object.getOwnPropertyNames(iterProto).sort(), ["next"]), true);
// StringIterator.prototype.next is a built-in function
assertBuiltinFunction(iterProto, "next", 0);
// StringIterator.prototype[@@iterator] is generic and returns |this|
for (var v of [void 0, null, true, false, "", 0, 1, {}, [], iter, iterProto]) {
assertEq(iterProto[Symbol.iterator].call(v), v);
}
// StringIterator.prototype.next is not generic
for (var v of [void 0, null, true, false, "", 0, 1, {}, [], iterProto]) {
assertThrowsInstanceOf(() => iterProto.next.call(v), TypeError);
}