forked from surma/rollup-plugin-off-main-thread
-
Notifications
You must be signed in to change notification settings - Fork 0
/
index.js
166 lines (140 loc) · 5.37 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
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
/**
* Copyright 2018 Google Inc. All Rights Reserved.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
const { readFileSync } = require("fs");
const { join } = require("path");
const ejs = require("ejs");
const MagicString = require("magic-string");
const defaultOpts = {
// A string containing the EJS template for the amd loader. If `undefined`,
// OMT will use `loader.ejs`.
loader: readFileSync(join(__dirname, "/loader.ejs"), "utf8"),
// Use `fetch()` + `eval()` to load dependencies instead of `<script>` tags
// and `importScripts()`. _This is not CSP compliant, but is required if you
// want to use dynamic imports in ServiceWorker_.
useEval: false,
// A RegExp to find `new Workers()` calls. The second capture group _must_
// capture the provided file name without the quotes.
workerRegexp: /new Worker\((["'])(.+?)\1\)/g,
// Function name to use instead of AMD’s `define`.
amdFunctionName: "define",
// A function that determines whether the loader code should be prepended to a
// certain chunk. Should return true if the load is supposed to be prepended.
prependLoader: (chunk, workerFiles) =>
chunk.isEntry || workerFiles.includes(chunk.facadeModuleId),
// The scheme used when importing workers as a URL.
urlLoaderScheme: "omt"
};
module.exports = function(opts = {}) {
opts = Object.assign({}, defaultOpts, opts);
opts.loader = ejs.render(opts.loader, opts);
const prefix = `"${opts.marker}_start" + import(`;
const suffix = `) + "${opts.marker}_end"`;
const urlLoaderPrefix = opts.urlLoaderScheme + ":";
let workerFiles;
return {
name: "off-main-thread",
async buildStart() {
workerFiles = [];
},
async resolveId(id, importer) {
if (!id.startsWith(urlLoaderPrefix)) return;
const path = id.slice(urlLoaderPrefix.length);
const newId = (await this.resolve(path, importer)).id;
if (!newId) throw Error(`Cannot find module '${path}'`);
return urlLoaderPrefix + newId;
},
load(id) {
if (!id.startsWith(urlLoaderPrefix)) return;
const realId = id.slice(urlLoaderPrefix.length);
const chunkRef = this.emitFile({ id: realId, type: "chunk" });
return `export default import.meta.ROLLUP_FILE_URL_${chunkRef};`;
},
async transform(code, id) {
// Copy the regexp as they are stateful and this hook is async.
const workerRegexp = new RegExp(
opts.workerRegexp.source,
opts.workerRegexp.flags
);
if (!workerRegexp.test(code)) {
return;
}
const ms = new MagicString(code);
// Reset the regexp
workerRegexp.lastIndex = 0;
while (true) {
const match = workerRegexp.exec(code);
if (!match) {
break;
}
const workerFile = match[2];
if (!new RegExp("^.*/").test(workerFile)) {
this.warn(
`Paths passed to the Worker constructor must be relative or absolute, i.e. start with /, ./ or ../ (just like dynamic import!). Ignoring "${workerFile}".`
);
continue;
}
const resolvedWorkerFile = await this.resolveId(workerFile, id);
workerFiles.push(resolvedWorkerFile);
const chunkRefId = this.emitFile({
id: resolvedWorkerFile,
type: "chunk"
});
const workerFileStartIndex = match.index + "new Worker(".length;
const workerFileEndIndex = match.index + match[0].length - ")".length;
ms.overwrite(
workerFileStartIndex,
workerFileEndIndex,
`import.meta.ROLLUP_FILE_URL_${chunkRefId}`
);
}
return {
code: ms.toString(),
map: ms.generateMap({ hires: true })
};
},
resolveFileUrl(chunk) {
return `"./${chunk.fileName}"`;
},
renderChunk(code, chunk, outputOptions) {
if (outputOptions.format !== "amd") {
this.error("You must set output.format to 'amd'");
return;
}
if (outputOptions.banner && outputOptions.banner.length > 0) {
this.error(
"OMT currently doesn’t work with `banner`. Feel free to submit a PR at https://github.com/surma/rollup-plugin-off-main-thread"
);
return;
}
const ms = new MagicString(code);
// Mangle define() call
const id = `./${chunk.fileName}`;
ms.remove(0, "define(".length);
// If the module does not have any dependencies, it’s technically okay
// to skip the dependency array. But our minimal loader expects it, so
// we add it back in.
if (!code.startsWith("define([")) {
ms.prepend("[],");
}
ms.prepend(`${opts.amdFunctionName}("${id}",`);
// Prepend loader if it’s an entry point or a worker file
if (opts.prependLoader(chunk, workerFiles)) {
ms.prepend(opts.loader);
}
return {
code: ms.toString(),
map: ms.generateMap({ hires: true })
};
}
};
};