function-bind.js 9.62 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
// Copyright 2010 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

28 29
// Flags: --allow-natives-syntax

30 31
// Tests the Function.prototype.bind method.

32 33 34

// Simple tests.
function foo(x, y, z) {
35
  return [this, arguments.length, x];
36 37
}

38 39
assertEquals(3, foo.length);

40
var f = foo.bind(foo);
41
assertEquals([foo, 3, 1], f(1, 2, 3));
42
assertEquals(3, f.length);
43
assertEquals("function () { [native code] }", f.toString());
44

45 46
f = foo.bind(foo, 1);
assertEquals([foo, 3, 1], f(2, 3));
47
assertEquals(2, f.length);
48
assertEquals("function () { [native code] }", f.toString());
49

50 51
f = foo.bind(foo, 1, 2);
assertEquals([foo, 3, 1], f(3));
52
assertEquals(1, f.length);
53
assertEquals("function () { [native code] }", f.toString());
54

55 56
f = foo.bind(foo, 1, 2, 3);
assertEquals([foo, 3, 1], f());
57
assertEquals(0, f.length);
58
assertEquals("function () { [native code] }", f.toString());
59 60 61 62

// Test that length works correctly even if more than the actual number
// of arguments are given when binding.
f = foo.bind(foo, 1, 2, 3, 4, 5, 6, 7, 8, 9);
63
assertEquals([foo, 9, 1], f());
64
assertEquals(0, f.length);
65
assertEquals("function () { [native code] }", f.toString());
66 67 68 69 70 71 72 73 74

// Use a different bound object.
var obj = {x: 42, y: 43};
// Values that would normally be in "this" when calling f_bound_this.
var x = 42;
var y = 44;

function f_bound_this(z) {
  return z + this.y - this.x;
75
}
76 77 78 79 80 81 82 83 84

assertEquals(3, f_bound_this(1))
f = f_bound_this.bind(obj);
assertEquals(2, f(1));
assertEquals(1, f.length);

f = f_bound_this.bind(obj, 2);
assertEquals(3, f());
assertEquals(0, f.length);
85
assertEquals('[object Function]', Object.prototype.toString.call(f));
86 87 88

// Test chained binds.

89
// When only giving the thisArg, any number of binds should have
90 91
// the same effect.
f = foo.bind(foo);
92 93 94 95 96
assertEquals([foo, 3, 1], f(1, 2, 3));

var not_foo = {};
f = foo.bind(foo).bind(not_foo).bind(not_foo).bind(not_foo);
assertEquals([foo, 3, 1], f(1, 2, 3));
97 98 99
assertEquals(3, f.length);

// Giving bound parameters should work at any place in the chain.
100 101
f = foo.bind(foo, 1).bind(not_foo).bind(not_foo).bind(not_foo);
assertEquals([foo, 3, 1], f(2, 3));
102 103
assertEquals(2, f.length);

104 105
f = foo.bind(foo).bind(not_foo, 1).bind(not_foo).bind(not_foo);
assertEquals([foo, 3, 1], f(2, 3));
106 107
assertEquals(2, f.length);

108 109
f = foo.bind(foo).bind(not_foo).bind(not_foo,1 ).bind(not_foo);
assertEquals([foo, 3, 1], f(2, 3));
110 111
assertEquals(2, f.length);

112 113
f = foo.bind(foo).bind(not_foo).bind(not_foo).bind(not_foo, 1);
assertEquals([foo, 3, 1], f(2, 3));
114 115
assertEquals(2, f.length);

116 117 118
// Several parameters can be given, and given in different bind invocations.
f = foo.bind(foo, 1, 2).bind(not_foo).bind(not_foo).bind(not_foo);
assertEquals([foo, 3, 1], f(3));
119 120
assertEquals(1, f.length);

121 122
f = foo.bind(foo).bind(not_foo, 1, 2).bind(not_foo).bind(not_foo);
assertEquals([foo, 3, 1], f(1));
123 124
assertEquals(1, f.length);

125 126
f = foo.bind(foo).bind(not_foo, 1, 2).bind(not_foo).bind(not_foo);
assertEquals([foo, 3, 1], f(3));
127 128
assertEquals(1, f.length);

129 130
f = foo.bind(foo).bind(not_foo).bind(not_foo, 1, 2).bind(not_foo);
assertEquals([foo, 3, 1], f(1));
131 132
assertEquals(1, f.length);

133 134
f = foo.bind(foo).bind(not_foo).bind(not_foo).bind(not_foo, 1, 2);
assertEquals([foo, 3, 1], f(3));
135 136
assertEquals(1, f.length);

137 138
f = foo.bind(foo, 1).bind(not_foo, 2).bind(not_foo).bind(not_foo);
assertEquals([foo, 3, 1], f(3));
139 140
assertEquals(1, f.length);

141 142
f = foo.bind(foo, 1).bind(not_foo).bind(not_foo, 2).bind(not_foo);
assertEquals([foo, 3, 1], f(3));
143 144
assertEquals(1, f.length);

145 146
f = foo.bind(foo, 1).bind(not_foo).bind(not_foo).bind(not_foo, 2);
assertEquals([foo, 3, 1], f(3));
147 148
assertEquals(1, f.length);

149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169
f = foo.bind(foo).bind(not_foo, 1).bind(not_foo).bind(not_foo, 2);
assertEquals([foo, 3, 1], f(3));
assertEquals(1, f.length);

// The wrong number of arguments can be given to bound functions too.
f = foo.bind(foo);
assertEquals(3, f.length);
assertEquals([foo, 0, undefined], f());
assertEquals([foo, 1, 1], f(1));
assertEquals([foo, 2, 1], f(1, 2));
assertEquals([foo, 3, 1], f(1, 2, 3));
assertEquals([foo, 4, 1], f(1, 2, 3, 4));

f = foo.bind(foo, 1);
assertEquals(2, f.length);
assertEquals([foo, 1, 1], f());
assertEquals([foo, 2, 1], f(2));
assertEquals([foo, 3, 1], f(2, 3));
assertEquals([foo, 4, 1], f(2, 3, 4));

f = foo.bind(foo, 1, 2);
170
assertEquals(1, f.length);
171 172 173 174 175 176 177 178 179 180 181 182
assertEquals([foo, 2, 1], f());
assertEquals([foo, 3, 1], f(3));
assertEquals([foo, 4, 1], f(3, 4));

f = foo.bind(foo, 1, 2, 3);
assertEquals(0, f.length);
assertEquals([foo, 3, 1], f());
assertEquals([foo, 4, 1], f(4));

f = foo.bind(foo, 1, 2, 3, 4);
assertEquals(0, f.length);
assertEquals([foo, 4, 1], f());
183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223

// Test constructor calls.

function bar(x, y, z) {
  this.x = x;
  this.y = y;
  this.z = z;
}

f = bar.bind(bar);
var obj2 = new f(1,2,3);
assertEquals(1, obj2.x);
assertEquals(2, obj2.y);
assertEquals(3, obj2.z);

f = bar.bind(bar, 1);
obj2 = new f(2,3);
assertEquals(1, obj2.x);
assertEquals(2, obj2.y);
assertEquals(3, obj2.z);

f = bar.bind(bar, 1, 2);
obj2 = new f(3);
assertEquals(1, obj2.x);
assertEquals(2, obj2.y);
assertEquals(3, obj2.z);

f = bar.bind(bar, 1, 2, 3);
obj2 = new f();
assertEquals(1, obj2.x);
assertEquals(2, obj2.y);
assertEquals(3, obj2.z);


// Test bind chains when used as a constructor.
f = bar.bind(bar, 1).bind(bar, 2).bind(bar, 3);
obj2 = new f();
assertEquals(1, obj2.x);
assertEquals(2, obj2.y);
assertEquals(3, obj2.z);

224
// Test obj2 is instanceof both bar and f.
225
assertTrue(obj2 instanceof bar);
226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274
assertTrue(obj2 instanceof f);

// This-args are not relevant to instanceof.
f = bar.bind(foo.prototype, 1).
    bind(String.prototype, 2).
    bind(Function.prototype, 3);
var obj3 = new f();
assertTrue(obj3 instanceof bar);
assertTrue(obj3 instanceof f);
assertFalse(obj3 instanceof foo);
assertFalse(obj3 instanceof Function);
assertFalse(obj3 instanceof String);

// thisArg is converted to object.
f = foo.bind(undefined);
assertEquals([this, 0, undefined], f());

f = foo.bind(null);
assertEquals([this, 0, undefined], f());

f = foo.bind(42);
assertEquals([Object(42), 0, undefined], f());

f = foo.bind("foo");
assertEquals([Object("foo"), 0, undefined], f());

f = foo.bind(true);
assertEquals([Object(true), 0, undefined], f());

// Strict functions don't convert thisArg.
function soo(x, y, z) {
  "use strict";
  return [this, arguments.length, x];
}

var s = soo.bind(undefined);
assertEquals([undefined, 0, undefined], s());

s = soo.bind(null);
assertEquals([null, 0, undefined], s());

s = soo.bind(42);
assertEquals([42, 0, undefined], s());

s = soo.bind("foo");
assertEquals(["foo", 0, undefined], s());

s = soo.bind(true);
assertEquals([true, 0, undefined], s());
275 276 277 278 279

// Test that .arguments and .caller are poisoned according to the ES5 spec.

// Check that property descriptors are correct (unconfigurable, unenumerable,
// and both get and set is the ThrowTypeError function).
280 281 282 283 284 285
//
// Poisoned accessors are no longer own properties --- get them from the
// prototype
var f_proto = Object.getPrototypeOf(f);
var cdesc = Object.getOwnPropertyDescriptor(f_proto, "caller");
var adesc = Object.getOwnPropertyDescriptor(f_proto, "arguments");
286 287

assertFalse(cdesc.enumerable);
288
assertTrue(cdesc.configurable);
289 290

assertFalse(adesc.enumerable);
291
assertTrue(adesc.configurable);
292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309

assertSame(cdesc.get, cdesc.set);
assertSame(cdesc.get, adesc.get);
assertSame(cdesc.get, adesc.set);

assertTrue(cdesc.get instanceof Function);
assertEquals(0, cdesc.get.length);
assertThrows(cdesc.get, TypeError);

assertThrows(function() { return f.caller; }, TypeError);
assertThrows(function() { f.caller = 42; }, TypeError);
assertThrows(function() { return f.arguments; }, TypeError);
assertThrows(function() { f.arguments = 42; }, TypeError);

// Shouldn't throw. Accessing the functions caller must throw if
// the caller is strict and the callee isn't. A bound function is built-in,
// but not considered strict.
(function foo() { return foo.caller; }).bind()();
310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326


(function TestProtoIsPreserved() {
  function fun() {}

  function proto() {}
  Object.setPrototypeOf(fun, proto);
  var bound = fun.bind({});
  assertEquals(proto, Object.getPrototypeOf(bound));

  var bound2 = fun.bind({});
  assertTrue(%HaveSameMap(new bound, new bound2));

  Object.setPrototypeOf(fun, null);
  bound = Function.prototype.bind.call(fun, {});
  assertEquals(null, Object.getPrototypeOf(bound));
})();