60 lines
1.0 KiB
Markdown
60 lines
1.0 KiB
Markdown
---
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title: Web workers
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category: JavaScript
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updated: 2017-10-30
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layout: 2017/sheet
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weight: -1
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---
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## Web workers
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#### Client
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```js
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var worker = new Worker('worker.js')
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worker.onmessage = function (message) {
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alert(JSON.stringify(message.data))
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})
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worker.postMessage('hello!')
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```
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Messages can be anything that can be serialized into JSON (objects, arrays, strings, numbers, booleans). See: [structured clone](https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm)
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#### Worker
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```js
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self.onmessage = function (message) {
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···
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}
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self.postMessage({ msg: 'hello' })
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```
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### Message data
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#### [MessageEvent]
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```js
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bubbles: false
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cancelBubble: false
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cancelable: false
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clipboardData: undefined
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currentTarget: Worker
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data: "Hello" ← the data
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defaultPrevented: false
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eventPhase: 0
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lastEventId: ""
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origin: ""
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ports: Array[0]
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returnValue: true
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source: null
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srcElement: Worker
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target: Worker
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timeStamp: 1344821022383
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type: "message"
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```
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These are the contents of `message` on onmessage.
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