45 lines
652 B
Markdown
45 lines
652 B
Markdown
---
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title: Immutable.js
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category: JavaScript libraries
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---
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### Maps
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```js
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var map = Immutable.Map({ a: 1, b: 2, c: 3 })
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```
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```js
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map
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.set('b', 50)
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.get('b') // 50
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```
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### Lists
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```js
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var list = Immutable.List.of(1, 2)
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list
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.push(3, 4, 5)
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.unshift(0)
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.concat(list2, list3)
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.get(0)
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.size
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```
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### Nested maps
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```js
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var nested = Immutable.fromJS({ user: { profile: { name: 'John' } } })
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nested
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// Update
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.mergeDeep({ user: { profile: { age: 90 } } })
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.setIn([ 'user', 'profile', 'name' ], 'Jack')
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.updateIn([ 'user', 'profile', 'name' ], (s) => s.toUpperCase())
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// Get
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.getIn(['user', 'profile', 'name']) // 'JACK'
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```
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