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34 lines
762 B
Markdown
34 lines
762 B
Markdown
---
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title: "06-async-javascript"
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aliases:
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tags:
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- lecture
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- cosc203
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---
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Async programming allows you to start a potentially long running task have still be able to interact while it it running
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general process
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- start the task
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- return immediately so other tasks can run
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- notify us with result when the task is finished
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promises
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- an object returned by an async function
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- represents the current state of the operation
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- when the promise is returned to the caller it not always finished
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- the promise object has methods to handle the eventual success or failure of the operation
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```
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const fetchPromise = fetch('https://url.url.json')
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fetchPromise
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.then((reponse) => {
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return response.json();
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})
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.then((data) => {
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console.log(data[0].name)
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})
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```
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