scanWhile

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

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

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

const array = require('extra-array');

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

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

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

References

• List-Extra.elemIndex: elm
• iterable-binsearch: @krisselden
• binarysearch: @soldair