🔄 Array.prototype.reduce() Polyfill
Category: js / polyfills
Difficulty: medium
The reduce() method executes a reducer function on each element of the array, resulting in a single output value. This polyfill is spec-compliant, handling edge cases like sparse arrays, missing initial values, and proper validation. ✅ Spec-Compliant Implementation [code example] ✅ How to Use [code example]...