重新排列对象数组的更有效方法？

Question

Hello fellow good devs,

I want to rearrange this the Array of objects ( array1 ) into the same order given in array2 ; as you may have noticed below, array2 is a simple array which its values are the same key names in array1, so you can say array2 is the 'arranging reference' for array1.

The below code worked for me as expected, but I am not happy with it, so much loops inside loops, i am afraid it may not be efficient.

I thought of using map() but I couldn't figure out how, is there any more efficient way for doing that by using map() or some other method?

Note: This is a server-side code, so I am not concerned about Browser compatibility.

            var array1 =
                [
                    { 'aaa': '1000', 'bbb': '2000' },
                    { 'aaa': '3333', 'bbb': '4444' }
                ]

            var array2 = ['bbb', 'aaa'];

            var reArrangedArr = [];


            array1.forEach(x => {
                var obj = {};
                for (i = 0; i < array2.length; i++) {
                    for (key in x) {
                        console.log(array2[i] + " " + key)
                        if (array2[i] === key) {
                            newKey = array2[i];
                            console.log("equal");
                            obj[newKey] = x[key]
                        }
                    }

                }
                reArrangedArr.push(obj);
            });


            console.log(reArrangedArr);

            ///output:  > Array [Object { bbb: "2000", aaa: "1000" }, Object { bbb: "4444", aaa: "3333" }]

Answer 1

You could map the array and map with Object.assign the keys and their values in the wanted order.

With spread syntax ... , a given iterable, like an array or string, is treated as parameters for the function call. Basically it is a syntactic suggar for function.apply(this, array) .

 var data = [{ aaa: '1000', bbb: '2000' }, { aaa: '3333', bbb: '4444' }], keys = ['bbb', 'aaa'], reordered = data.map(o => Object.assign(...keys.map(k => ({ [k]: o[k] })))); console.log(reordered); 

 .as-console-wrapper { max-height: 100% !important; top: 0; } 

Answer 2

You can use Array.reduce() operation to achieve that:

  var array1 = [ { 'aaa': '1000', 'bbb': '2000' }, { 'aaa': '3333', 'bbb': '4444' } ]; var array2 = ['bbb', 'aaa']; var reArrangedArr = array1.reduce((acc, obj) => { var tempObj = {}; array2.forEach(item => tempObj[item] = obj[item]); acc.push(tempObj); return acc; }, []); console.log(reArrangedArr);