-
Notifications
You must be signed in to change notification settings - Fork 1.1k
/
substr.js
66 lines (56 loc) · 2.07 KB
/
substr.js
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
65
66
module.exports = function substr(input, start, len) {
// discuss at: https://locutus.io/php/substr/
// original by: Martijn Wieringa
// bugfixed by: T.Wild
// improved by: Onno Marsman (https://twitter.com/onnomarsman)
// improved by: Brett Zamir (https://brett-zamir.me)
// revised by: Theriault (https://github.com/Theriault)
// revised by: Rafał Kukawski
// note 1: Handles rare Unicode characters if 'unicode.semantics' ini (PHP6) is set to 'on'
// example 1: substr('abcdef', 0, -1)
// returns 1: 'abcde'
// example 2: substr(2, 0, -6)
// returns 2: false
// example 3: ini_set('unicode.semantics', 'on')
// example 3: substr('a\uD801\uDC00', 0, -1)
// returns 3: 'a'
// example 4: ini_set('unicode.semantics', 'on')
// example 4: substr('a\uD801\uDC00', 0, 2)
// returns 4: 'a\uD801\uDC00'
// example 5: ini_set('unicode.semantics', 'on')
// example 5: substr('a\uD801\uDC00', -1, 1)
// returns 5: '\uD801\uDC00'
// example 6: ini_set('unicode.semantics', 'on')
// example 6: substr('a\uD801\uDC00z\uD801\uDC00', -3, 2)
// returns 6: '\uD801\uDC00z'
// example 7: ini_set('unicode.semantics', 'on')
// example 7: substr('a\uD801\uDC00z\uD801\uDC00', -3, -1)
// returns 7: '\uD801\uDC00z'
// test: skip-3 skip-4 skip-5 skip-6 skip-7
const _php_cast_string = require('../_helpers/_phpCastString') // eslint-disable-line camelcase
input = _php_cast_string(input)
const ini_get = require('../info/ini_get') // eslint-disable-line camelcase
const multibyte = ini_get('unicode.semantics') === 'on'
if (multibyte) {
input = input.match(/[\uD800-\uDBFF][\uDC00-\uDFFF]|[\s\S]/g) || []
}
const inputLength = input.length
let end = inputLength
if (start < 0) {
start += end
}
if (typeof len !== 'undefined') {
if (len < 0) {
end = len + end
} else {
end = len + start
}
}
if (start > inputLength || start < 0 || start > end) {
return false
}
if (multibyte) {
return input.slice(start, end).join('')
}
return input.slice(start, end)
}