Overleaf/services/web/public/js/libs/polyfills/array-fill.js

define([], function() {
  if (!Array.prototype.fill) {
    Object.defineProperty(Array.prototype, 'fill', {
      value: function (value) {

        // Steps 1-2.
        if (this == null) {
          throw new TypeError('this is null or not defined');
        }

        var O = Object(this);

        // Steps 3-5.
        var len = O.length >>> 0;

        // Steps 6-7.
        var start = arguments[1];
        var relativeStart = start >> 0;

        // Step 8.
        var k = relativeStart < 0 ?
          Math.max(len + relativeStart, 0) :
          Math.min(relativeStart, len);

        // Steps 9-10.
        var end = arguments[2];
        var relativeEnd = end === undefined ?
          len : end >> 0;

        // Step 11.
        var final = relativeEnd < 0 ?
          Math.max(len + relativeEnd, 0) :
          Math.min(relativeEnd, len);

        // Step 12.
        while (k < final) {
          O[k] = value;
          k++;
        }

        // Step 13.
        return O;
      }
    });
  }
})