webwackify

Inspired heavily by webworkify and webworkify-webpack-dropin

launch a web worker that can require() in the browser with browserify and webpack

example

First, a main.js file will launch the worker.js and print its output:

`` js
var resolveWorker = function() {
var result;

try {
result = require.resolve('./worker.js');
} catch (e) {}

return result;
};

var work = require('webworkify');

var w = work(require('./worker.js'), resolveWorker());
w.addEventListener('message', function (ev) {
console.log(ev.data);
});

w.postMessage(4); // send the worker a message
`

then worker.js can require() modules of its own.

NOTE: resolveWorker() is used because he module id of the worker is required to pass along with the worker when webpack is used to bundle the project. Webpack will resolve module ids at build time by replacing calls to require.resolve. Browserify does not do this however, and we have to resolve the module ids ourselves using the dependency graph provided by browserify, so the try{}catch{} is added to prevent runtime errors.

The worker function lives
inside of the module.exports:

` js
var gamma = require('gamma');

module.exports = function (self) {
self.addEventListener('message',function (ev){
var startNum = parseInt(ev.data); // ev.data=4 from main.js

setInterval(function () {
var r = startNum / Math.random() - 1;
self.postMessage([ startNum, r, gamma(r) ]);
}, 500);
});
};
`

Now after browserifying this example, the console will
contain output from the worker:

`
[ 4, 0.09162078520553618, 10.421030346237066 ]
[ 4, 2.026562457360466, 1.011522336481017 ]
[ 4, 3.1853125018703716, 2.3887589540750214 ]
[ 4, 5.6989969260510005, 72.40768854476167 ]
[ 4, 8.679491643020487, 20427.19357947782 ]
[ 4, 0.8528139834191428, 1.1098187157762498 ]
[ 4, 8.068322137547542, 5785.928308309402 ]
...
`

methods

` js
var work = require('webworkify')
`

var w = work(require(modulePath), moduleId)

Return a new
web worker
from the module at modulePath.

The file at modulePath should export its worker code in module.exports as a
function that will be run with no arguments.

Note that all the code outside of the module.exports function will be run in
the main thread too so don't put any computationally intensive code in that
part. It is necessary for the main code to require() the worker code to fetch
the module reference and load modulePath's dependency graph into the bundle
output.

moduleId is required when bundling with webpack. You can get the moduleId by calling require.resolve(modulePath). It is suggested to use a resolveWorker() function like in the above example to avoid runtime errors when bundled with browserify.

` js
var resolveWorker = function() {
var result;

try {
result = require.resolve(modulePath);
} catch (e) {}

return result;
};
`

Worker.objectURL

The worker w returned by webworkify has the property objectURL attached.
w.objectURL refers to the Object URL that was used to pass the module's source
to the worker, and can be cleaned up using URL.revokeObjectURL(). (See example)

install

With npm do:

`
npm install webwackify
``

license

MIT