Like filter, but negated

Array.prototype.reject.js

/*
  # `Array.prototype.reject`

  ## Summary

  Like `filter`, except negated.

  **Example:**

  ```js
  [1, 2, 3].reject(n => n % 2 === 0);
  // [1, 3]
  ```

  **Syntax**

  ```
  reject(callback: Function, context?: Any) => Array
  ```
*/

if (!Array.prototype.reject) {
  Array.prototype.reject = function (callbackFn) {
    return this.reduce((newArray, item) => {
      return !callbackFn(item) ? newArray.concat([item]) : newArray;
    }, []);
  }
}