Check if two arrays intersect

JavaScript, Array · Feb 17, 2023

Determines if two arrays have a common item.

Create a Set from b to get the unique values in b.
Use Array.prototype.some() on a to check if any of its values are contained in b, using Set.prototype.has().

const intersects = (a, b) => {
  const s = new Set(b);
  return [...new Set(a)].some(x => s.has(x));
};

intersects(['a', 'b'], ['b', 'c']); // true
intersects(['a', 'b'], ['c', 'd']); // false

Written by Angelos Chalaris

I'm Angelos Chalaris, a JavaScript software engineer, based in Athens, Greece. The best snippets from my coding adventures are published here to help others learn to code.

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