34 lines
1.1 KiB
Markdown
34 lines
1.1 KiB
Markdown
---
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title: Map Function
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---
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## The Map Function
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The `map()` function is used for creating a new array from an existing one, applying a function to each one of the elements of the first array.
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The original syntax of the map function is:
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```javascript
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let new_arr = arr.map(function callback(currentValue, index, array) {
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// Do some stuff with currentValue (index and array are optionals)
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})
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```
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* `new_arr` - the new array that is returned
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* `ar`r - the array to run the map function on
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* `currentValue` - the current value being processed
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* `index` - the current index of the value being processed
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* `array` - the original array
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### Example (ES6):
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```javascript
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const myArray_1 = [1, 2, 3, 4];
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const myArray_2 = myArray_1.map(el => el * 2);
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```
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`myArray_2` will contain the elements: `[2, 4, 6, 8]`
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`map()` is a method of the `Array` object, so to pass that function to an iterable object it is necessary to make the object an Array.
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### Resources:
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[MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map)
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