tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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string-iterator-surfaces.js (2739B)

      1 // String.prototype[@@iterator] and StringIterator.prototype surface tests
      2 
      3 load(libdir + "array-compare.js");
      4 load(libdir + "asserts.js");
      5 load(libdir + "iteration.js");
      6 
      7 function assertDataDescriptor(actual, expected) {
      8    assertEq(actual.value, expected.value);
      9    assertEq(actual.writable, expected.writable);
     10    assertEq(actual.enumerable, expected.enumerable);
     11    assertEq(actual.configurable, expected.configurable);
     12 }
     13 
     14 function isConstructor(o) {
     15    try {
     16        new (new Proxy(o, {construct: () => ({})}));
     17        return true;
     18    } catch(e) {
     19        return false;
     20    }
     21 }
     22 
     23 function assertBuiltinFunction(o, name, arity) {
     24    var fn = o[name];
     25    assertDataDescriptor(Object.getOwnPropertyDescriptor(o, name), {
     26        value: fn,
     27        writable: true,
     28        enumerable: false,
     29        configurable: true,
     30    });
     31 
     32    assertEq(typeof fn, "function");
     33    assertEq(Object.getPrototypeOf(fn), Function.prototype);
     34    assertEq(isConstructor(fn), false);
     35 
     36    assertEq(arraysEqual(Object.getOwnPropertyNames(fn).sort(), ["length", "name"].sort()), true);
     37 
     38    assertDataDescriptor(Object.getOwnPropertyDescriptor(fn, "length"), {
     39        value: arity,
     40        writable: false,
     41        enumerable: false,
     42        configurable: true
     43    });
     44 
     45    var functionName = typeof name === "symbol"
     46                       ? String(name).replace(/^Symbol\((.+)\)$/, "[$1]")
     47                       : name;
     48    assertDataDescriptor(Object.getOwnPropertyDescriptor(fn, "name"), {
     49        value: functionName,
     50        writable: false,
     51        enumerable: false,
     52        configurable: true
     53    });
     54 }
     55 
     56 
     57 // String.prototype[@@iterator] is a built-in function
     58 assertBuiltinFunction(String.prototype, Symbol.iterator, 0);
     59 
     60 // Test StringIterator.prototype surface
     61 var iter = ""[Symbol.iterator]();
     62 var iterProto = Object.getPrototypeOf(iter);
     63 
     64 // StringIterator.prototype inherits from %IteratorPrototype%. Check it's the
     65 // same object as %ArrayIteratorPrototype%'s proto.
     66 assertEq(Object.getPrototypeOf(iterProto),
     67         Object.getPrototypeOf(Object.getPrototypeOf([][Symbol.iterator]())));
     68 
     69 // Own properties for StringIterator.prototype: "next"
     70 assertEq(arraysEqual(Object.getOwnPropertyNames(iterProto).sort(), ["next"]), true);
     71 
     72 // StringIterator.prototype.next is a built-in function
     73 assertBuiltinFunction(iterProto, "next", 0);
     74 
     75 // StringIterator.prototype[@@iterator] is generic and returns |this|
     76 for (var v of [void 0, null, true, false, "", 0, 1, {}, [], iter, iterProto]) {
     77    assertEq(iterProto[Symbol.iterator].call(v), v);
     78 }
     79 
     80 // StringIterator.prototype.next is not generic
     81 for (var v of [void 0, null, true, false, "", 0, 1, {}, [], iterProto]) {
     82    assertThrowsInstanceOf(() => iterProto.next.call(v), TypeError);
     83 }