forked from addyosmani/critical
-
Notifications
You must be signed in to change notification settings - Fork 0
/
index.js
148 lines (125 loc) · 3.65 KB
/
index.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
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
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
/*
* critical
* http://github.com/addyosmani/critical
*/
'use strict';
var fs = require('fs');
var path = require('path');
var penthouse = require('penthouse');
var CleanCSS = require('clean-css');
var oust = require('oust');
var inliner = require('./inline-styles');
/**
* Critical path CSS generation
* @param {object} opts Options
* @param {function} cb Callback
* @accepts src, base, width, height, dest
*/
exports.generate = function (opts, cb) {
opts = opts || {};
cb = cb || function () {};
if (!opts.src || !opts.base) {
throw new Error('A valid source and base path are required.');
}
if (!opts.height) {
opts.height = 320;
}
if (!opts.width) {
opts.width = 480;
}
var url = path.join(opts.base, opts.src);
fs.readFile(url, function (err, html) {
if (err) {
cb(err);
return;
}
// Oust extracts a list of your stylesheets
var hrefs = oust(html, 'stylesheets');
// Penthouse then determines your critical
// path CSS using these as input.
penthouse({
url: url,
css: path.join(opts.base, hrefs[0]),
// What viewports do you care about?
width: opts.width, // viewport width
height: opts.height // viewport height
}, function (err, criticalCSS) {
if (err) {
cb(err);
return;
}
if (opts.minify === true) {
criticalCSS = new CleanCSS().minify(criticalCSS);
}
if (opts.dest) {
// Write critical-path CSS
fs.writeFile(path.join(opts.base, opts.dest), criticalCSS, function (err) {
if (err) {
cb(err);
return;
}
cb(null, criticalCSS.toString());
});
} else {
cb(null, criticalCSS.toString());
}
});
});
};
/**
* Critical path CSS inlining
* @param {object} opts Options
* @param {function} cb Callback
* @accepts src, base, dest
*/
exports.inline = function (opts, cb) {
opts = opts || {};
cb = cb || function () {};
if (!opts.src || !opts.base) {
throw new Error('A valid source and base path are required.');
}
// Inline the critical path CSS
fs.readFile(path.join(opts.base, opts.src), function (err, data) {
if (err) {
cb(err);
return;
}
var out = inliner(data, opts.base, opts.minify);
if (opts.dest) {
// Write HTML with inlined CSS to dest
fs.writeFile(path.join(opts.base, opts.dest), out, function (err) {
if (err) {
cb(err);
return;
}
cb(null, out.toString());
});
} else {
cb(null, out.toString());
}
});
};
/**
* Generate and inline critical-path CSS
* @param {object} opts Options
* @param {function} cb Callback
* @accepts src, base, width, height, styleTarget, htmlTarget
*/
exports.generateInline = function (opts, cb) {
opts = opts || {};
cb = cb || function () {};
if (!opts.styleTarget || !opts.htmlTarget) {
throw new Error('Valid style and HTML targets are required.');
}
var genOpts = opts;
var inlineOpts = opts;
genOpts.dest = opts.styleTarget;
exports.generate(genOpts, function (err, output) {
if (err) {
cb(err);
return;
}
inlineOpts.dest = opts.htmlTarget;
exports.inline(inlineOpts);
});
};