how to use the foldr function from the underscore library in javascript

The _.foldr() function, also known as reduceRight(), is part of the Underscore library, which is a functional programming library for JavaScript. _.foldr() applies a function against an accumulator and each value of an array from right to left, reducing it to a single value.

Syntax:

index.tsx
_.foldr(array, iteratee, accumulator, [context])
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Parameters:

• array: The input array to iterate over.
• iteratee: The function to apply to each element in the array.
• accumulator: Used to keep track of the computation progress.
• context (optional): this keyword context for iteratee function.

Example usage:

index.tsx
const _ = require('underscore');  // Import the underscore library

const arr = [1, 2, 3, 4, 5];

const sum = _.foldr(arr, function(accumulator, currentValue) {
  return accumulator + currentValue;
}, 0);

console.log(sum); // Output: 15
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In this example, _.foldr() applies the function of adding two numbers -- the iteratee function -- to each element of the array starting from the right side of the array. The accumulator starts with a value of 0, to which the result of each computation is added. At the end, the final result is the sum of all the numbers in the array, which is logged to the console.