takeWhile

Keep values from left, while a test passes.

Alternatives: take, takeRight, takeWhile, takeWhileRight.
Similar: take, drop.

function takeWhile(x, ft)
// x:  an iterable
// ft: test function (v, i, x)

const xiterable = require('extra-iterable');

var x = [1, 2, 3, 4, 5];
[...xiterable.takeWhile(x, v => v < 3)];
// → [1, 2]

[...xiterable.takeWhile(x, v => v < 4)];
// → [1, 2, 3]

References

• Data.List.takeWhile: Haskell
• Array.prototype.slice: MDN web docs