前言
由于在编写代码时经常遇见如下报错信息，找到原因后在此做个小总结
解析
1、变量未定义：当我们在尚未定义或未初始化的变量上设置属性，就会出现此错误
let obj; obj.name = 'aaa';//throw the error
要解决此问题，我们可以在设置属性之前使用空对象或适当的初始值
let obj = {};
obj.name = 'aaa';
2、对象为 null 或者 undefined：当我们给值为 null 或者 undefined 的变量设置属性时也将遇到此错误
let obj = null; obj.name = 'aaa';//throw the error
- 215 properties TypeError undefined setting215 properties typeerror undefined properties typeerror undefined reading properties typeerror undefined uncaught typeerror undefined property cannot typeerror undefined uncaught property typeerror non-mysql undefined property typeerror undefined property upgrade typeerror undefined property webpack quot properties typeerror undefined properties typeerror undefined时报