24 lines
721 B
Markdown
24 lines
721 B
Markdown
### isSorted
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Returns `1` if the array is sorted in ascending order, `-1` if it is sorted in descending order or `0` if it is not sorted.
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Calculate the ordering `direction` for the first two elements.
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Use `Object.entries()` to loop over array objects and compare them in pairs.
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Return `0` if the `direction` changes or the `direction` if the last element is reached.
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```js
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const isSorted = arr => {
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const direction = arr[0] > arr[1] ? -1 : 1;
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for (let [i, val] of arr.entries())
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if (i === arr.length - 1) return direction;
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else if ((val - arr[i + 1]) * direction > 0) return 0;
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};
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```
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```js
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isSorted([0, 1, 2, 3]); // 1
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isSorted([0, 1, 2, 2]); // 1
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isSorted([4, 3, 2]); // -1
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isSorted([4, 3, 5]); // 0
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```
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