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
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
// Copyright (C) 2016 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-addition-operator-plus-runtime-semantics-evaluation
es6id: 12.7.3.1
description: Invocation of `Symbol.toPrimitive` method during coercion
info: |
[...]
5. Let lprim be ? ToPrimitive(lval).
6. Let rprim be ? ToPrimitive(rval).
[...]
ES6 Section 7.2.12 Abstract Equality Comparison
[...]
10. If Type(x) is either String, Number, or Symbol and Type(y) is Object,
then return the result of the comparison x == ToPrimitive(y).
ES6 Section 7.1.1 ToPrimitive ( input [, PreferredType] )
1. If PreferredType was not passed, let hint be "default".
[...]
4. Let exoticToPrim be GetMethod(input, @@toPrimitive).
5. ReturnIfAbrupt(exoticToPrim).
6. If exoticToPrim is not undefined, then
a. Let result be Call(exoticToPrim, input, «hint»).
[...]
features: [Symbol.toPrimitive]
---*/
var left = {};
var right = {};
var log = '';
var leftThisVal, rightThisVal, leftArgs, rightArgs;
left[Symbol.toPrimitive] = function() {
log += 'left';
leftThisVal = this;
leftArgs = arguments;
};
right[Symbol.toPrimitive] = function() {
log += 'right';
rightThisVal = this;
rightArgs = arguments;
};
left + right;
assert.sameValue(log, 'leftright', 'methods invoked in correct sequence');
assert.sameValue(leftThisVal, left, 'left-hand side `this` value');
assert.sameValue(leftArgs.length, 1, 'left-hand side argument length');
assert.sameValue(leftArgs[0], 'default', 'left-hand side argument value');
assert.sameValue(rightThisVal, right, 'right-hand side `this` value');
assert.sameValue(rightArgs.length, 1, 'right-hand side argument length');
assert.sameValue(rightArgs[0], 'default', 'right-hand side argument value');
|
