var test = require('tape'); var functionBind = require('../implementation'); var getCurrentContext = function () { return this; }; test('functionBind is a function', function (t) { t.equal(typeof functionBind, 'function'); t.end(); }); test('non-functions', function (t) { var nonFunctions = [true, false, [], {}, 42, 'foo', NaN, /a/g]; t.plan(nonFunctions.length); for (var i = 0; i < nonFunctions.length; ++i) { try { functionBind.call(nonFunctions[i]); } catch (ex) { t.ok(ex instanceof TypeError, 'throws when given ' + String(nonFunctions[i])); } } t.end(); }); test('without a context', function (t) { t.test('binds properly', function (st) { var args, context; var namespace = { func: functionBind.call(function () { args = Array.prototype.slice.call(arguments); context = this; }) }; namespace.func(1, 2, 3); st.deepEqual(args, [1, 2, 3]); st.equal(context, getCurrentContext.call()); st.end(); }); t.test('binds properly, and still supplies bound arguments', function (st) { var args, context; var namespace = { func: functionBind.call(function () { args = Array.prototype.slice.call(arguments); context = this; }, undefined, 1, 2, 3) }; namespace.func(4, 5, 6); st.deepEqual(args, [1, 2, 3, 4, 5, 6]); st.equal(context, getCurrentContext.call()); st.end(); }); t.test('returns properly', function (st) { var args; var namespace = { func: functionBind.call(function () { args = Array.prototype.slice.call(arguments); return this; }, null) }; var context = namespace.func(1, 2, 3); st.equal(context, getCurrentContext.call(), 'returned context is namespaced context'); st.deepEqual(args, [1, 2, 3], 'passed arguments are correct'); st.end(); }); t.test('returns properly with bound arguments', function (st) { var args; var namespace = { func: functionBind.call(function () { args = Array.prototype.slice.call(arguments); return this; }, null, 1, 2, 3) }; var context = namespace.func(4, 5, 6); st.equal(context, getCurrentContext.call(), 'returned context is namespaced context'); st.deepEqual(args, [1, 2, 3, 4, 5, 6], 'passed arguments are correct'); st.end(); }); t.test('called as a constructor', function (st) { var thunkify = function (value) { return function () { return value; }; }; st.test('returns object value', function (sst) { var expectedReturnValue = [1, 2, 3]; var Constructor = functionBind.call(thunkify(expectedReturnValue), null); var result = new Constructor(); sst.equal(result, expectedReturnValue); sst.end(); }); st.test('does not return primitive value', function (sst) { var Constructor = functionBind.call(thunkify(42), null); var result = new Constructor(); sst.notEqual(result, 42); sst.end(); }); st.test('object from bound constructor is instance of original and bound constructor', function (sst) { var A = function (x) { this.name = x || 'A'; }; var B = functionBind.call(A, null, 'B'); var result = new B(); sst.ok(result instanceof B, 'result is instance of bound constructor'); sst.ok(result instanceof A, 'result is instance of original constructor'); sst.end(); }); st.end(); }); t.end(); }); test('with a context', function (t) { t.test('with no bound arguments', function (st) { var args, context; var boundContext = {}; var namespace = { func: functionBind.call(function () { args = Array.prototype.slice.call(arguments); context = this; }, boundContext) }; namespace.func(1, 2, 3); st.equal(context, boundContext, 'binds a context properly'); st.deepEqual(args, [1, 2, 3], 'supplies passed arguments'); st.end(); }); t.test('with bound arguments', function (st) { var args, context; var boundContext = {}; var namespace = { func: functionBind.call(function () { args = Array.prototype.slice.call(arguments); context = this; }, boundContext, 1, 2, 3) }; namespace.func(4, 5, 6); st.equal(context, boundContext, 'binds a context properly'); st.deepEqual(args, [1, 2, 3, 4, 5, 6], 'supplies bound and passed arguments'); st.end(); }); t.test('returns properly', function (st) { var boundContext = {}; var args; var namespace = { func: functionBind.call(function () { args = Array.prototype.slice.call(arguments); return this; }, boundContext) }; var context = namespace.func(1, 2, 3); st.equal(context, boundContext, 'returned context is bound context'); st.notEqual(context, getCurrentContext.call(), 'returned context is not lexical context'); st.deepEqual(args, [1, 2, 3], 'passed arguments are correct'); st.end(); }); t.test('returns properly with bound arguments', function (st) { var boundContext = {}; var args; var namespace = { func: functionBind.call(function () { args = Array.prototype.slice.call(arguments); return this; }, boundContext, 1, 2, 3) }; var context = namespace.func(4, 5, 6); st.equal(context, boundContext, 'returned context is bound context'); st.notEqual(context, getCurrentContext.call(), 'returned context is not lexical context'); st.deepEqual(args, [1, 2, 3, 4, 5, 6], 'passed arguments are correct'); st.end(); }); t.test('passes the correct arguments when called as a constructor', function (st) { var expected = { name: 'Correct' }; var namespace = { Func: functionBind.call(function (arg) { return arg; }, { name: 'Incorrect' }) }; var returned = new namespace.Func(expected); st.equal(returned, expected, 'returns the right arg when called as a constructor'); st.end(); }); t.test('has the new instance\'s context when called as a constructor', function (st) { var actualContext; var expectedContext = { foo: 'bar' }; var namespace = { Func: functionBind.call(function () { actualContext = this; }, expectedContext) }; var result = new namespace.Func(); st.equal(result instanceof namespace.Func, true); st.notEqual(actualContext, expectedContext); st.end(); }); t.end(); }); test('bound function length', function (t) { t.test('sets a correct length without thisArg', function (st) { var subject = functionBind.call(function (a, b, c) { return a + b + c; }); st.equal(subject.length, 3); st.equal(subject(1, 2, 3), 6); st.end(); }); t.test('sets a correct length with thisArg', function (st) { var subject = functionBind.call(function (a, b, c) { return a + b + c; }, {}); st.equal(subject.length, 3); st.equal(subject(1, 2, 3), 6); st.end(); }); t.test('sets a correct length without thisArg and first argument', function (st) { var subject = functionBind.call(function (a, b, c) { return a + b + c; }, undefined, 1); st.equal(subject.length, 2); st.equal(subject(2, 3), 6); st.end(); }); t.test('sets a correct length with thisArg and first argument', function (st) { var subject = functionBind.call(function (a, b, c) { return a + b + c; }, {}, 1); st.equal(subject.length, 2); st.equal(subject(2, 3), 6); st.end(); }); t.test('sets a correct length without thisArg and too many arguments', function (st) { var subject = functionBind.call(function (a, b, c) { return a + b + c; }, undefined, 1, 2, 3, 4); st.equal(subject.length, 0); st.equal(subject(), 6); st.end(); }); t.test('sets a correct length with thisArg and too many arguments', function (st) { var subject = functionBind.call(function (a, b, c) { return a + b + c; }, {}, 1, 2, 3, 4); st.equal(subject.length, 0); st.equal(subject(), 6); st.end(); }); });