Fundamentals / Arrays
Arrays: map, filter, reduce
Transform, select, and combine — without writing manual loops.
`map` produces a new array by transforming every element. `filter` produces a new array keeping only elements that pass a test. `reduce` collapses an array down to a single value by carrying an accumulator through each element. All three leave the original array untouched.
Codeeditable — Run and Step both follow your edits
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Console
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Visualization
Element by Element
Step through to watch each element get processed
Why?
map calls your function once per element and collects the return values into a brand-new array — the original array is never mutated.