微信PC客户端不支持object.assign方法

Recently, I encountered a bug: my frontend project can work normally in WeChat mobile clients but when visited in WeChat PC client for window OS, the page turned out be be blank -_-. After some attempts, I found that it’s due to the unavailability of Object.assign method in WeChat PC client for window OS.

Therefore, we need to write polyfill for Object.assign method. There is not need to think how to write this polyfill ourselves. Just copy from MDN ^_^.

if (typeof Object.assign != 'function') {
  // Must be writable: true, enumerable: false, configurable: true
  Object.defineProperty(Object, "assign", {
    value: function assign(target, varArgs) { // .length of function is 2
      'use strict';
      if (target == null) { // TypeError if undefined or null
        throw new TypeError('Cannot convert undefined or null to object');
      }

      var to = Object(target);

      for (var index = 1; index < arguments.length; index++) {
        var nextSource = arguments[index];

        if (nextSource != null) { // Skip over if undefined or null
          for (var nextKey in nextSource) {
            // Avoid bugs when hasOwnProperty is shadowed
            if (Object.prototype.hasOwnProperty.call(nextSource, nextKey)) {
              to[nextKey] = nextSource[nextKey];
            }
          }
        }
      }
      return to;
    },
    writable: true,
    configurable: true
  });
}

The code is from: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign

Yakima Teng,

August 28, 2017

In Shanghai, China