# json

json 常用语法

# 修改json中的key值

const data = [
              {count:335, goods:'直接访问'},
              {count:310, goods:'邮件营销'},
              {count:234, goods:'联盟广告'}
            ].map(function(item) {
                return {
                    name: item.goods,
                    value: item.count
                }
            });
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# 判断json数组中是否含有值

let arr=["a","b","c"];
let arr2={"a":"aaa","b":"bbb","c":"ccc"};

// in判断是否在数组的key里
console.log("1:","a" in arr);  // false
console.log("2:","aa" in arr);  // false
console.log("3:",2 in arr);  // true
console.log("4:",5 in arr);  // false
console.log("5:","a" in arr2);  // true
console.log("6:","aa" in arr2);  // false
// indexOf列表(字符串)是否包含
console.log("7:",arr.indexOf("c"));  // 2
console.log("8:",arr.indexOf("aa"));  // -1
console.log("9:",arr2.indexOf("b"));  //报错
console.log("10:",arr2.indexOf("aaa"));  //报错
// includes用于列表和字符串
console.log("11:",arr.includes("a"));  // true
console.log("12:",arr.includes("aa"));  // false
console.log("13:",arr2.includes("a"));  //报错
console.log("14:",arr2.includes("aa"));  //报错

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Last Updated: 5/24/2024, 2:37:16 AM