json8-pointer/lib/validArrayToken.js

JSON Pointer toolkit for JavaScript

"use strict";

/**
 * Check if the token is a valid array token and throws an error
 *
 * @param  {String} token        - token
 * @param  {Number} arrayLength  - array length
 * @return {undefined}
 */
module.exports = function validArrayToken(token, arrayLength) {
  if (token === "-") return;

  const error = new Error("Invalid pointer");
  const length = token.length;

  if (length > 1 && token[0] === "0") throw error;

  const idx = +token;

  if (isNaN(idx)) throw error;

  if (Math.abs(idx).toString() !== token) throw error;

  if (idx < 0) throw error;

  if (idx > arrayLength) throw error;
};