JavaScript: Get a list of elements that exist in both arrays, using a provided comparator function

JavaScript fundamental (ES6 Syntax): Exercise-209 with Solution

Common Elements by Comparator

Write a JavaScript program to get a list of elements in both arrays, using a provided comparator function.

• Use Array.prototype.filter() and Array.prototype.findIndex() in combination with the provided comparator to determine intersecting values.

Sample Solution:

JavaScript Code:

// Define a function 'intersectionWith' that computes the intersection of two arrays based on a custom comparator function
const intersectionWith = (a, b, comp) => 
  a.filter(x => 
    // Filter elements from array 'a' that have a matching element in array 'b' based on the custom comparator function 'comp'
    b.findIndex(y => comp(x, y)) !== -1
  );

// Test the 'intersectionWith' function by finding the intersection of two arrays with a custom comparator function
console.log(intersectionWith([1, 1.2, 1.5, 3, 0], [1.9, 3, 0, 3.9], (a, b) => Math.round(a) === Math.round(b)));
// Output: [1.5, 3, 0]

Output:

[1.5,3,0]

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-209-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that returns a list of common elements between two arrays using a custom comparator function.
• Write a JavaScript function that compares each element of one array to every element of another using a comparator and collects matches.
• Write a JavaScript program that uses a nested loop and a comparator to identify shared elements between arrays.
• Write a JavaScript function that leverages filter and some methods with a custom comparator to find intersections.

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