blob: 70ff48da20fdb5d43659aad682278a6d615bf978 (
plain)
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
60
61
62
63
64
|
/**
* Copyright (c) 2013-present, Facebook, Inc.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
*
*/
'use strict';
var enumerate = require('./enumerate');
/**
* Checks if two iterables are equal. A custom areEqual function may be provided
* as an optional third argument.
*/
function equalsIterable(one, two, areEqual) {
if (one === two) {
return true;
}
// We might be able to short circuit by using the size or length fields.
var oneSize = maybeGetSize(one);
var twoSize = maybeGetSize(two);
if (oneSize != null && twoSize != null && oneSize !== twoSize) {
return false;
}
// Otherwise use the iterators to check equality. Here we cannot use for-of
// because we need to advance the iterators at the same time.
var oneIterator = enumerate(one);
var oneItem = oneIterator.next();
var twoIterator = enumerate(two);
var twoItem = twoIterator.next();
var safeAreEqual = areEqual || referenceEquality;
while (!(oneItem.done || twoItem.done)) {
if (!safeAreEqual(oneItem.value, twoItem.value)) {
return false;
}
oneItem = oneIterator.next();
twoItem = twoIterator.next();
}
return oneItem.done === twoItem.done;
}
function maybeGetSize(o) {
if (o == null) {
return null;
}
if (typeof o.size === 'number') {
return o.size;
}
if (typeof o.length === 'number') {
return o.length;
}
return null;
}
function referenceEquality(one, two) {
return one === two;
}
module.exports = equalsIterable;
|
