diff --git a/test/built-ins/Function/prototype/bind/instance-length-default-value.js b/test/built-ins/Function/prototype/bind/instance-length-default-value.js new file mode 100644 index 0000000000..86d22724d8 --- /dev/null +++ b/test/built-ins/Function/prototype/bind/instance-length-default-value.js @@ -0,0 +1,52 @@ +// Copyright (C) 2020 Alexey Shvayka. All rights reserved. +// This code is governed by the BSD license found in the LICENSE file. + +/*--- +esid: sec-function.prototype.bind +description: > + "length" value of a bound function defaults to 0. + Non-own and non-number "length" values of target function are ignored. +info: | + Function.prototype.bind ( thisArg, ...args ) + + [...] + 5. Let targetHasLength be ? HasOwnProperty(Target, "length"). + 6. If targetHasLength is true, then + a. Let targetLen be ? Get(Target, "length"). + b. If Type(targetLen) is not Number, let L be 0. + c. Else, + i. Set targetLen to ! ToInteger(targetLen). + ii. Let L be the larger of 0 and the result of targetLen minus the number of elements of args. + 7. Else, let L be 0. + 8. Perform ! SetFunctionLength(F, L). + [...] +features: [Symbol] +---*/ + +function foo() {} + +Object.defineProperty(foo, "length", {value: undefined}); +assert.sameValue(foo.bind(null, 1).length, 0, "undefined"); + +Object.defineProperty(foo, "length", {value: null}); +assert.sameValue(foo.bind(null, 1).length, 0, "null"); + +Object.defineProperty(foo, "length", {value: true}); +assert.sameValue(foo.bind(null, 1).length, 0, "boolean"); + +Object.defineProperty(foo, "length", {value: "1"}); +assert.sameValue(foo.bind(null, 1).length, 0, "string"); + +Object.defineProperty(foo, "length", {value: Symbol("1")}); +assert.sameValue(foo.bind(null, 1).length, 0, "symbol"); + +Object.defineProperty(foo, "length", {value: new Number(1)}); +assert.sameValue(foo.bind(null, 1).length, 0, "Number object"); + + +function bar() {} +Object.setPrototypeOf(bar, {length: 42}); +assert(delete bar.length); + +var bound = Function.prototype.bind.call(bar, null, 1); +assert.sameValue(bound.length, 0, "not own");