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/*
* Any copyright is dedicated to the Public Domain.
*/
var gTestfile = 'function-bind.js';
var BUGNUMBER = 429507;
var summary = "ES5: Function.prototype.bind";
print(BUGNUMBER + ": " + summary);
/**************
* BEGIN TEST *
**************/
// ad-hoc testing
assertEq(Function.prototype.hasOwnProperty("bind"), true);
var bind = Function.prototype.bind;
assertEq(bind.length, 1);
var strictReturnThis = function() { "use strict"; return this; };
assertEq(strictReturnThis.bind(undefined)(), undefined);
assertEq(strictReturnThis.bind(null)(), null);
var obj = {};
assertEq(strictReturnThis.bind(obj)(), obj);
assertEq(strictReturnThis.bind(NaN)(), NaN);
assertEq(strictReturnThis.bind(true)(), true);
assertEq(strictReturnThis.bind(false)(), false);
assertEq(strictReturnThis.bind("foopy")(), "foopy");
// rigorous, step-by-step testing
function expectThrowTypeError(fun)
{
assertThrowsInstanceOf(fun, TypeError);
}
/*
* 1. Let Target be the this value.
* 2. If IsCallable(Target) is false, throw a TypeError exception.
*/
expectThrowTypeError(function() { bind.call(null); });
expectThrowTypeError(function() { bind.call(undefined); });
expectThrowTypeError(function() { bind.call(NaN); });
expectThrowTypeError(function() { bind.call(0); });
expectThrowTypeError(function() { bind.call(-0); });
expectThrowTypeError(function() { bind.call(17); });
expectThrowTypeError(function() { bind.call(42); });
expectThrowTypeError(function() { bind.call("foobar"); });
expectThrowTypeError(function() { bind.call(true); });
expectThrowTypeError(function() { bind.call(false); });
expectThrowTypeError(function() { bind.call([]); });
expectThrowTypeError(function() { bind.call({}); });
/*
* 3. Let A be a new (possibly empty) internal list of all of the argument
* values provided after thisArg (arg1, arg2 etc), in order.
* 4. Let F be a new native ECMAScript object .
* 5. Set all the internal methods, except for [[Get]], of F as specified in
* 8.12.
* 6. Set the [[Get]] internal property of F as specified in 15.3.5.4.
* 7. Set the [[TargetFunction]] internal property of F to Target.
* 8. Set the [[BoundThis]] internal property of F to the value of thisArg.
* 9. Set the [[BoundArgs]] internal property of F to A.
*/
// throughout
/* 10. Set the [[Class]] internal property of F to "Function". */
var toString = Object.prototype.toString;
assertEq(toString.call(function(){}), "[object Function]");
assertEq(toString.call(function a(){}), "[object Function]");
assertEq(toString.call(function(a){}), "[object Function]");
assertEq(toString.call(function a(b){}), "[object Function]");
assertEq(toString.call(function(){}.bind()), "[object Function]");
assertEq(toString.call(function a(){}.bind()), "[object Function]");
assertEq(toString.call(function(a){}.bind()), "[object Function]");
assertEq(toString.call(function a(b){}.bind()), "[object Function]");
/*
* 11. Set the [[Prototype]] internal property of F to the standard built-in
* Function prototype object as specified in 15.3.3.1.
*/
assertEq(Object.getPrototypeOf(bind.call(function(){})), Function.prototype);
assertEq(Object.getPrototypeOf(bind.call(function a(){})), Function.prototype);
assertEq(Object.getPrototypeOf(bind.call(function(a){})), Function.prototype);
assertEq(Object.getPrototypeOf(bind.call(function a(b){})), Function.prototype);
/*
* 12. Set the [[Call]] internal property of F as described in 15.3.4.5.1.
*/
var a = Array.bind(1, 2);
assertEq(a().length, 2);
assertEq(a(4).length, 2);
assertEq(a(4, 8).length, 3);
function t() { return this; }
var bt = t.bind(t);
assertEq(bt(), t);
function callee() { return arguments.callee; }
var call = callee.bind();
assertEq(call(), callee);
assertEq(new call(), callee);
/*
* 13. Set the [[Construct]] internal property of F as described in 15.3.4.5.2.
*/
function Point(x, y)
{
this.x = x;
this.y = y;
}
var YAxisPoint = Point.bind(null, 0)
assertEq(YAxisPoint.hasOwnProperty("prototype"), false);
var p = new YAxisPoint(5);
assertEq(p.x, 0);
assertEq(p.y, 5);
assertEq(p instanceof Point, true);
assertEq(p instanceof YAxisPoint, true);
assertEq(Object.prototype.toString.call(YAxisPoint), "[object Function]");
assertEq(YAxisPoint.length, 1);
/*
* 14. Set the [[HasInstance]] internal property of F as described in
* 15.3.4.5.3.
*/
function JoinArguments()
{
this.args = Array.prototype.join.call(arguments, ", ");
}
var Join1 = JoinArguments.bind(null, 1);
var Join2 = Join1.bind(null, 2);
var Join3 = Join2.bind(null, 3);
var Join4 = Join3.bind(null, 4);
var Join5 = Join4.bind(null, 5);
var Join6 = Join5.bind(null, 6);
var r = new Join6(7);
assertEq(r instanceof Join6, true);
assertEq(r instanceof Join5, true);
assertEq(r instanceof Join4, true);
assertEq(r instanceof Join3, true);
assertEq(r instanceof Join2, true);
assertEq(r instanceof Join1, true);
assertEq(r instanceof JoinArguments, true);
assertEq(r.args, "1, 2, 3, 4, 5, 6, 7");
/*
* 15. If the [[Class]] internal property of Target is "Function", then
* a. Let L be the length property of Target minus the length of A.
* b. Set the length own property of F to either 0 or L, whichever is larger.
* 16. Else set the length own property of F to 0.
*/
function none() { return arguments.length; }
assertEq(none.bind(1, 2)(3, 4), 3);
assertEq(none.bind(1, 2)(), 1);
assertEq(none.bind(1)(2, 3), 2);
assertEq(none.bind().length, 0);
assertEq(none.bind(null).length, 0);
assertEq(none.bind(null, 1).length, 0);
assertEq(none.bind(null, 1, 2).length, 0);
function one(a) { }
assertEq(one.bind().length, 1);
assertEq(one.bind(null).length, 1);
assertEq(one.bind(null, 1).length, 0);
assertEq(one.bind(null, 1, 2).length, 0);
// retch
var br = Object.create(null, { length: { value: 0 } });
try
{
br = bind.call(/a/g, /a/g, "aaaa");
}
catch (e) { /* nothing */ }
assertEq(br.length, 0);
/*
* 17. Set the attributes of the length own property of F to the values
* specified in 15.3.5.1.
*/
var len1Desc =
Object.getOwnPropertyDescriptor(function(a, b, c){}.bind(), "length");
assertEq(len1Desc.value, 3);
assertEq(len1Desc.writable, false);
assertEq(len1Desc.enumerable, false);
assertEq(len1Desc.configurable, true);
var len2Desc =
Object.getOwnPropertyDescriptor(function(a, b, c){}.bind(null, 2), "length");
assertEq(len2Desc.value, 2);
assertEq(len2Desc.writable, false);
assertEq(len2Desc.enumerable, false);
assertEq(len2Desc.configurable, true);
/*
* 18. Set the [[Extensible]] internal property of F to true.
*/
var bound = (function() { }).bind();
var isExtensible = Object.isExtensible || function() { return true; };
assertEq(isExtensible(bound), true);
bound.foo = 17;
var fooDesc = Object.getOwnPropertyDescriptor(bound, "foo");
assertEq(fooDesc.value, 17);
assertEq(fooDesc.writable, true);
assertEq(fooDesc.enumerable, true);
assertEq(fooDesc.configurable, true);
/*
* Steps 19-21 are removed from ES6, instead implemented through "arguments" and
* "caller" accessors on Function.prototype. So no own properties, but do check
* for the same observable behavior (modulo where the accessors live).
*/
function strict() { "use strict"; }
function nonstrict() {}
function testBound(fun)
{
var boundf = fun.bind();
assertEq(Object.getOwnPropertyDescriptor(boundf, "arguments"), undefined,
"should be no arguments property");
assertEq(Object.getOwnPropertyDescriptor(boundf, "caller"), undefined,
"should be no caller property");
expectThrowTypeError(function() { return boundf.arguments; });
expectThrowTypeError(function() { return boundf.caller; });
}
testBound(strict);
testBound(nonstrict);
var nativeFunctionRegex = /^function\s*\(\)\s*{\s*\[native code\]\s*}$/
assertEq(nativeFunctionRegex.test((function unbound(){"body"}).bind().toString()), true);
/* 22. Return F. */
var passim = function p(){}.bind(1);
assertEq(typeof passim, "function");
/******************************************************************************/
if (typeof reportCompare === "function")
reportCompare(true, true);
print("All tests passed!");