scanWhile

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Subhajit Sahu edited this page Feb 3, 2021 · 11 revisions

Scans from left, while a test passes. 🏃 📼 📦 🌔 📒

Alternatives: scanWhile, scanWhileRight, scanUntil, scanUntilRight.
Similar: search, scan, find.

iterable.scanWhile(x, ft);
// x:  an iterable
// ft: test function (v, i, x)
// --> index where test fails

const iterable = require("extra-iterable");

var x = [1, 1, 2, 2, 3, 3, 4, 4];
iterable.scanWhile(x, v => v % 2 !== 0);
// 2           ^

iterable.scanWhile(x, v => v % 3 !== 0);
// 4                 ^

iterable.scanWhile(x, v => v % 6 !== 0);
// 8                            ^

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