function scanWhile(x, ft) // x: an array // ft: test function (v, i, x)

const xiterable = require('extra-iterable'); var x = [1, 1, 2, 2, 3, 3, 4, 4]; xiterable.scanWhile(x, v => v % 2 !== 0); // → 2 ^ xiterable.scanWhile(x, v => v % 3 !== 0); // → 4 ^ xiterable.scanWhile(x, v => v % 6 !== 0); // → 8 ^