/**
   * Simple memoize
   * wxs doesn't support fn.apply, so this memoize only support up to 2 args
   */
  
  function isPrimitive(value) {
    var type = typeof value;
    return (
      type === 'boolean' ||
      type === 'number' ||
      type === 'string' ||
      type === 'undefined' ||
      value === null
    );
  }
  
  // mock simple fn.call in wxs
  function call(fn, args) {
    if (args.length === 2) {
      return fn(args[0], args[1]);
    }
  
    if (args.length === 1) {
      return fn(args[0]);
    }
  
    return fn();
  }
  
  function serializer(args) {
    if (args.length === 1 && isPrimitive(args[0])) {
      return args[0];
    }
    var obj = {};
    for (var i = 0; i < args.length; i++) {
      obj['key' + i] = args[i];
    }
    return JSON.stringify(obj);
  }
  
  function memoize(fn) {
    var cache = {};
  
    return function() {
      var key = serializer(arguments);
      if (cache[key] === undefined) {
        cache[key] = call(fn, arguments);
      }
  
      return cache[key];
    };
  }
  
  module.exports.memoize = memoize;