EN
JavaScript - resize array
6 points
In this short article, we would like to show how to resize array in JavaScript.
Quick solution (ES6+):
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const resizeArray = (array, newSize) => {2
const changeSize = newSize - array.length;3
if (changeSize > 0) {4
return array.concat(Array(changeSize).fill(0));5
}6
return array.slice(0, newSize);7
};8
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// Usage example:11
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const array = [1, 2, 3, 4, 5];13
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const array1 = resizeArray(array, 3); // new size=3 so: [1, 2, 3]15
const array2 = resizeArray(array, 10); // new size=10 so: [1, 2, 3, 4, 5, 6, 0, 0, 0, 0]16
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console.log(JSON.stringify(array1)); // [1, 2, 3]18
console.log(JSON.stringify(array2)); // [1, 2, 3, 4, 5, 6, 0, 0, 0, 0]
Sometimes we want to use a solution that works in older JavaScript (ES5).
The below code shows how to do it:
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function createArray(count) {2
var array = Array(count);3
for (var i = 0; i < count; ++i) {4
array[i] = 0;5
}6
return array;7
}8
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function resizeArray(array, newSize) {10
var changeSize = newSize - array.length;11
if (changeSize > 0) {12
return array.concat(createArray(changeSize));13
} else {14
return array.slice(0, newSize);15
}16
}17
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// Usage example:20
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var array = [1, 2, 3, 4, 5];22
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var array1 = resizeArray(array, 3); // new size=3 so: [1, 2, 3]24
var array2 = resizeArray(array, 10); // new size=10 so: [1, 2, 3, 4, 5, 6, 0, 0, 0, 0]25
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console.log(JSON.stringify(array1)); // [1, 2, 3]27
console.log(JSON.stringify(array2)); // [1, 2, 3, 4, 5, 6, 0, 0, 0, 0]
