关于#javascript#的问题：

Question

num是总体的数据，b,c是分数据

如果b数组中的对象里面有num中的某一项，则把这一项从num中拿出来放到b中
如果c数组中的对象里面有num中的某几项，则把这几项从num中拿出来放到c中

 var num = [{a:1,b:2,c:3},{a:1,b:2,c:3},{a:1,b:2,c:3}];
 var b = []
    // var b = [{a:1},{a:1},{a:1}];
 var c =[]
   // var c = [{a:1,b:2},{a:1,b:2},{a:1,b:2}]

Answer 1

var num = [{a: 1, b: 2, c: 3}, {a: 1, b: 2, c: 3}, {a: 1, b: 2, c: 3}];
// 比如b中用到了a属性
var b = []
var result_b = [{a: 1}, {a: 1}, {a: 1}]
//c中用到了b，c属性
var c = []
var result_c = [{b: 2, c: 3}, {b: 2, c: 3}, {b: 2, c: 3}]


function selectField(data, fields) {
    return data.map(item => fields.reduce((t, i) => {
        if (item[i] != null && item[i] != undefined) {
            t[i] = item[i]
        }
        return t
    }, {})).filter(item => Object.keys(item).length != 0)
}

console.log(selectField(num, ['a']))
console.log(selectField(num, ['b', 'c']))