Remove array elements until condition is met
JavaScript, Array · Nov 29, 2020

Removes elements in an array until the passed function returns true
.
Returns the removed elements.
- Loop through the array, using a
for...of
loop overArray.prototype.entries()
until the returned value from the function is truthy. - Return the removed elements, using
Array.prototype.slice()
. - The callback function,
fn
, accepts a single argument which is the value of the element.
const takeUntil = (arr, fn) => { for (const [i, val] of arr.entries()) if (fn(val)) return arr.slice(0, i); return arr; }; takeUntil([1, 2, 3, 4], n => n >= 3); // [1, 2]