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Accumulating some value over using a callback function and initial value in JavaScript
Problem
We are required to write a JavaScript function that takes in an array a callback function and an initial value.
The function should accumulate a value over the iteration of array and finally return the value just like the Array.prototype.reduce() does.
Example
Following is the code −
const arr = [1, 2, 3, 4, 5];
const sum = (a, b) => a + b;
Array.prototype.customReduce = function(callback, initial){
if(!initial){
initial = this[0];
};
let res = initial;
for(let i = initial === this[0] ? 1 : 0; i < this.length; i++){
res = callback(res, this[i]);
};
return res;
};
console.log(arr.customReduce(sum, 0));Output
Following is the console output −
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Updated on: 17-Apr-2021
131 Views
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