30-seconds-of-code/snippets/count-occurrences.md

title, type, tags, cover, dateModified

title	type	tags	cover	dateModified
Count occurrences	snippet	array	dark-leaves-4	2020-10-18T23:04:45+03:00

Counts the occurrences of a value in an array.

• Use Array.prototype.reduce() to increment a counter each time the specific value is encountered inside the array.

const countOccurrences = (arr, val) =>
  arr.reduce((a, v) => (v === val ? a + 1 : a), 0);

countOccurrences([1, 1, 2, 1, 2, 3], 1); // 3