js中常见错误类型的总结

1. ReferenceError(引用错误)

function sayHi(){
      console.log(age);
      let age = 21;
   }
   sayHi()

2、TypeError（类型错误）

var result = (function(){
      var x = 1,y = 2;
      sum = x + y
       return sum;
 })()
result()

3.RangeError：范围错误

       var num = 0;
        function fun() {
            console.log(++num)
            fun()
        }
        fun()

 4.SyntaxError（语法错误）

var a = 7;
var 1num = 3;
function(){
    console.log(a);
}