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davidnagli/cdup.js

Created January 14, 2018 21:52
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cdup-js : count duplicates in a javascript array (find the count of each unique element in an array) with this simple, easy, and FAST one liner
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cdup.js
// Readable version:
array.reduce((countsMap, item) => countsMap.set(item, countsMap.get(item) + 1 || 1), new Map)
// Minified version:
array.reduce((a,b)=>a.set(b,a.get(b)+1||1),new Map)
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