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

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

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:

//#Source https://bit.ly/2neWfJ2 
const intersection = (a, b) => {
  const s = new Set(b);
  return a.filter(x => s.has(x));
};
console.log(intersection([1, 2, 3], [4, 3, 2]));

Sample Output:

[2,3]

Pictorial Presentation:

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

Flowchart:

flowchart: Get a list of elements that exist in both arrays.

Live Demo:

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


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Previous: Write a JavaScript program to get a list of elements that exist in both arrays, after applying the provided function to each array element of both.
Next: Write a JavaScript program to create a n-dimensional array with given value.

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JavaScript: Tips of the Day

How to check whether a string contains a substring in JavaScript?

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";

console.log(string.includes(substring));

includes doesn't have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found:

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Ref: https://bit.ly/3fFFgZv