code: function sanicShift(array) {
      if (!(array instanceof Array)) {
          throw new TypeError('array is not an Array');
      }
      if (!array.length) {
          return undefined;
      }
  
      let oldElement = array[0];
  
      let i = 1;
      const iMax = array.length;
  
      for (; i < iMax; i++) {
          array[i-1] = array[i];
      }
  
      array.length--;
  
      return oldElement;
  }
docs: /* Tested :
  - reverse, array.length--, reverse