Count Truthy Values

Fundamentals: Part 1medium

Course · Section 2: JavaScript Fundamentals – Part 1 · Lecture 11: Data Types

Implement `countTruthy(arr)` returning how many elements of `arr` are truthy.

Input: countTruthy([0,1,2,"",null,"a"])

Output: 3

Input: countTruthy([false,0,""])

Output: 0

+ 1 hidden test run on Submit.

Common pitfalls

Counting with a manual loop and == comparisons invites coercion bugs; Boolean is clearer.

Approach & explanation (try first)

filter(Boolean) drops every falsy element, so its length is the number of truthy values.

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Run your code to see results.