if (typeof (jsonStrOrObj) === 'string') {
    jsonStrOrObj = JSON.parse(jsonStrOrObj);
}
 
 
var str1 = '1';
var str2 = '2';
var str3 = '1';
var num = 1;
console.log(str1 == str2); // false
console.log(str1 == str3); // true
console.log(str1 == num); // true
console.log(str1 === num); // false
 
=== 不会进行类型转换 ,类型不同直接不相等
判断字符串相等 ，推荐 使用 ===
 
 
var arr = [1, 2, 3];
arr.push(4);
arr.push(null);
arr.length
var map = {}
map.name = 'tiger';
map.name
map['name']
 
数组遍历
for(var i=0;i < arr.length;i++){
    console.log(arr[i])
}
Object.entries(map)
Object.keys(map)

var a = {"name":"tiger"}
var s = JSON.stringify(a)
var a2 = JSON.parse(s);



var m = {'key1':1,'key2':2};
var keys = Object.keys(m);
for(var i=0;i < keys.length ; i++){console.log(m[keys[i]]);}

var kvs = Object.entries(m);
for(var i=0;i < kvs.length ; i++){console.log(kvs[i][0]+"="+kvs[i][1]);}