Fill array with one value 'n' times

fillArrayWithConcat.js

// Fill array with value, len times
// Using concat
fillArray = (value, len) => {
    if (len === 0) return [];
    let a = [value];
    while (a.length * 2 <= len) a = a.concat(a);
    if (a.length < len) a = a.concat(a.slice(0, len - a.length));
    return a;
  };

fillArrayWithPush.js

// Fill array with value, len times
// Using push
fillArray = (value, len) => {
    const arr = [];
    for (let i = 0; i < len; i += 1) {
      arr.push(value);
    }
    return arr;
  };

fillArrayWithSpread.js

// Fill array with value, len times
// Using spread operator
const fillArray = (value, len) => {
    let arr = [];
    for (let i = 0; i < len; i += 1) {
      arr = [...arr, value];
    }
    return arr;
  };