unit.js
2.23 KB
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
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
var minus = "-".charCodeAt(0);
var plus = "+".charCodeAt(0);
var dot = ".".charCodeAt(0);
var exp = "e".charCodeAt(0);
var EXP = "E".charCodeAt(0);
// Check if three code points would start a number
// https://www.w3.org/TR/css-syntax-3/#starts-with-a-number
function likeNumber(value) {
var code = value.charCodeAt(0);
var nextCode;
if (code === plus || code === minus) {
nextCode = value.charCodeAt(1);
if (nextCode >= 48 && nextCode <= 57) {
return true;
}
var nextNextCode = value.charCodeAt(2);
if (nextCode === dot && nextNextCode >= 48 && nextNextCode <= 57) {
return true;
}
return false;
}
if (code === dot) {
nextCode = value.charCodeAt(1);
if (nextCode >= 48 && nextCode <= 57) {
return true;
}
return false;
}
if (code >= 48 && code <= 57) {
return true;
}
return false;
}
// Consume a number
// https://www.w3.org/TR/css-syntax-3/#consume-number
module.exports = function(value) {
var pos = 0;
var length = value.length;
var code;
var nextCode;
var nextNextCode;
if (length === 0 || !likeNumber(value)) {
return false;
}
code = value.charCodeAt(pos);
if (code === plus || code === minus) {
pos++;
}
while (pos < length) {
code = value.charCodeAt(pos);
if (code < 48 || code > 57) {
break;
}
pos += 1;
}
code = value.charCodeAt(pos);
nextCode = value.charCodeAt(pos + 1);
if (code === dot && nextCode >= 48 && nextCode <= 57) {
pos += 2;
while (pos < length) {
code = value.charCodeAt(pos);
if (code < 48 || code > 57) {
break;
}
pos += 1;
}
}
code = value.charCodeAt(pos);
nextCode = value.charCodeAt(pos + 1);
nextNextCode = value.charCodeAt(pos + 2);
if (
(code === exp || code === EXP) &&
((nextCode >= 48 && nextCode <= 57) ||
((nextCode === plus || nextCode === minus) &&
nextNextCode >= 48 &&
nextNextCode <= 57))
) {
pos += nextCode === plus || nextCode === minus ? 3 : 2;
while (pos < length) {
code = value.charCodeAt(pos);
if (code < 48 || code > 57) {
break;
}
pos += 1;
}
}
return {
number: value.slice(0, pos),
unit: value.slice(pos)
};
};