json对象赋值

obj = {"1":"a";"2":"b";"3":"c";"4":"d"}

a = ["1","2","3"]

newObj={}

将json对象obj里面key在数组a里面的对象，放入newObj的json对象中

this.a.forEach(item => {
   this.newObj[item]=this.obj[item]
})

结果：newObj = {"1":"a";"2":"b";"3":"c"}