javascript - JS 中合并数组

Question

假设我有以下数组:

var first = [
    { id: 1, name: 'first' },
    { id: 2, name: 'second' },
    { id: 3, name: 'third' }
]

var second = [
    { id: 2, field: 'foo2' },
    { id: 3, field: 'foo3' },
    { id: 4, field: 'foo4' }
]

var third = [
    { id: 2, data: 'some2' },
    { id: 5, data: 'some5' },
    { id: 6, data: 'some6' }
]

我想合并它们以获得以下结果:

var result = [
    { id: 1, name: 'first',   field: undefined, data: undefined },
    { id: 2, name: 'second',  field: 'foo2',    data: 'some2' },
    { id: 3, name: 'third',   field: 'foo3',    data: undefined },
    { id: 4, name: undefined, field: 'foo4',    data: undefined },
    { id: 5, name: undefined, field: undefined, data: 'some5' },
    { id: 6, name: undefined, field: undefined, data: 'some6' }
]

我怎样才能用 JavaScript 做到这一点？

Answer 1

您应该获取所有现有的键，并在创建新对象并填充“空”键后:

function mergeArrays(){
    var keys = {};
    //save all existed keys
    for(var i=arguments.length;--i;){
        for(var j=arguments[i].length;--j;){
            for(var key in arguments[i][j]){
                keys[key] = true;
            }
        }
    }

    var res = [];
    for(var i=arguments.length;--i;){
        for(var j=arguments[i].length;--j;){
            //set clone of object
            var clone = JSON.parse(JSON.stringify(arguments[i][j]));
            for(var key in keys){
                if(!(key in clone)){
                    clone[key] = undefined;
                }
            }
            res.push(clone);
        }
    }

    return res;
}

https://jsfiddle.net/x3b0tk3g/