code: function $slice(params) {
      if (
          Array.isArray(params) &&
          (params.length === 2 || params.length === 3) &&
          Array.isArray(params[0]) &&
          typeof params[1] === 'number' &&
          (params[2] === undefined || typeof params[2] === 'number')
      ) {
          return params[0].slice(params[1], params[2]);
      }
      throw new Error(
          '$slice expects an array of two or three elements of which the first must be an array and the second/third be a number'
      );
  }
docs: Slice an array from the given index to an optional end index
  
  @param {[any[], number]|[any[], number, number]} params
  @returns {any[]}