JavaScript 循环 跳出循环问题
例如有这么两组数据
let a = [
{
"value": "S",
"id": 1
},
{
"value": "M",
"id": 2
},
{
"value": "L",
"id": 3
},
{
"value": "XL",
"id": 4
},
{
"value": "XXL",
"id": 5
},
{
"value": "XXXL",
"id": 6
}
]
let b = [1,2,3,4];
需求是这样的:如果 a 下 有 b下的值 给 对应a下添加 haseB = true
//二重循环? 跑一下看看
a.map((itema)=>{
b.map((itemb)=>{
itema.id === itemb?
itema.haseB = true
// 要跳出呀,然后继续执行,但是没 continue,加个return 看下呢?
:
null
})
})
console.log(JSON.stringify(a))
[{"value":"S","id":1,"haseB":false},
{"value":"M","id":2,"haseB":false},
{"value":"L","id":3,"haseB":false},
{"value":"XL","id":4,"haseB":true},
{"value":"XXL","id":5,"haseB":false},
{"value":"XXXL","id":6,"haseB":false}]
//加 return false 结果 emm, 符合预期
[{"value":"S","id":1,"haseB":true},
{"value":"M","id":2,"haseB":true},
{"value":"L","id":3,"haseB":true},
{"value":"XL","id":4,"haseB":true},
{"value":"XXL","id":5},
{"value":"XXXL","id":6}]
//另外一个奇巧技淫
a.map((itema)=>{
b.find((e)=>{
if(itema.id===e){
itema.haseB=true
return e
}
})
})
介绍下find用法:
·
**find()**
方法返回数组中满足提供的测试函数的第一个元素的值。否则返回 undefined
·
var array1 = [5, 12, 8, 130, 44];
var found = array1.find(function(element) {
return element > 10;
});
console.log(found);
// expected output: 12
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