Inputmask/lib/polyfills/Array.includes.js

// https://tc39.github.io/ecma262/#sec-array.prototype.includes
if (!Array.prototype.includes) {
  // eslint-disable-next-line no-extend-native
  Object.defineProperty(Array.prototype, "includes", {
    value: function (searchElement, fromIndex) {
      // 1. Let O be ? ToObject(this value).
      if (this == null) {
        throw new TypeError('"this" is null or not defined');
      }

      const o = Object(this),
        // 2. Let len be ? ToLength(? Get(O, "length")).
        len = o.length >>> 0;

      // 3. If len is 0, return false.
      if (len === 0) {
        return false;
      }

      // 4. Let n be ? ToInteger(fromIndex).
      //    (If fromIndex is undefined, this step produces the value 0.)
      let n = fromIndex | 0,
        // 5. If n ≥ 0, then
        //  a. Let k be n.
        // 6. Else n < 0,
        //  a. Let k be len + n.
        //  b. If k < 0, let k be 0.
        k = Math.max(n >= 0 ? n : len - Math.abs(n), 0);

      // 7. Repeat, while k < len
      while (k < len) {
        // a. Let elementK be the result of ? Get(O, ! ToString(k)).
        // b. If SameValueZero(searchElement, elementK) is true, return true.
        // c. Increase k by 1.
        // NOTE: === provides the correct "SameValueZero" comparison needed here.
        if (o[k] === searchElement) {
          return true;
        }
        k++;
      }

      // 8. Return false
      return false;
    }
  });
}