JavaScript

lazy pipeline in JavaScript

JavaScriptGeneratorsgenerator compositionadvanced

What this snippet does

Generator pipelines are entirely lazy — no intermediate arrays are created, and values are computed only as consumed.

Expected output

[ 0, 4, 16, 36, 64 ]

Why practise typing this

Typing generators code builds muscle memory for the symbols and indentation JavaScript uses most, which prose-based typing tests never cover. DevType measures your words per minute and accuracy on this snippet and tracks the individual characters you mistype, so later lessons can target them.

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