JavaScript: Get a list of elements that exist in both arrays

JavaScript fundamental (ES6 Syntax): Exercise-211 with Solution

Common Elements in Arrays

Write a JavaScript program to get a list of elements that exist in both arrays.

• Create a Set from b, then use Array.prototype.filter() on a to only keep values contained in b.

Sample Solution:

JavaScript Code:

// Define a function 'intersection' that computes the intersection of two arrays
const intersection = (a, b) => {
  // Create a Set 's' containing the elements of array 'b'
  const s = new Set(b);
  // Filter elements from array 'a' if they exist in the Set 's'
  return a.filter(x => s.has(x));
};

// Test the 'intersection' function by finding the intersection of two arrays
console.log(intersection([1, 2, 3], [4, 3, 2]));
// Output: [2, 3]

Output:

[2,3]

visual Presentation:

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-211-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript program that returns the intersection of two arrays without using a comparator function.
• Write a JavaScript function that filters one array to include only elements that exist in the other.
• Write a JavaScript program that uses Set operations to compute the common elements between two arrays.
• Write a JavaScript function that iterates over two arrays and collects shared values into a new array.

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