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15a1a3c014
* add initial function * add initial test case * add initial bench mark * add initial docs
50 lines
1.0 KiB
Markdown
50 lines
1.0 KiB
Markdown
# initial
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Returns a new array containing all elements except the last one from the input array.
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For an empty array or an array with a length of 1, it returns an empty array (`[]`).
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## Signature
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```typescript
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function initial<T>(arr: T[]): T[];
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```
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### Parameters
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- `arr` (`T[]`): The array from which to return all elements except the last one.
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### Returns
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(T[]): A new array containing all elements except the last one from the input array. For an empty array or an array with a length of 1, it returns an empty array ([]).
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## Examples
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```typescript
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const arr1 = [1, 2, 3];
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const result = initial(arr1);
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// result is [1, 2].
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const arr2: number[] = [];
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const result = initial(arr2);
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// result is [].
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const arr3: number[] = [1];
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const result = initial(arr3);
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// result is [].
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const largeArray = Array(1000)
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.fill(0)
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.map((_, i) => i);
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const result = initial(largeArray);
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// result is [0, 1, 2 ..., 998].
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const nestedArray = [
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[3, 1],
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[3, 2],
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[3, 3],
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];
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const result = initial(nestedArray);
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// result is [[3, 1], [3, 2]].
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```
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