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30-seconds-of-code/snippets/count-occurrences-of-a-value-in-array.md
Angelos Chalaris 542a4f94b1 Deep flatten and housekeeping
Changed original flatten to be named deepFlatten, added normal flatten, improved some other snippets.
2017-12-12 18:12:24 +02:00

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Count occurrences of a value in array

Use reduce() to increment a counter each time you encounter the specific value inside the array.

const countOccurrences = (arr, value) => arr.reduce((a, v) => v === value ? a + 1 : a + 0, 0);
// countOccurrences([1,1,2,1,2,3], 1) -> 3