Lodash。 通过键智能合并两个对象

Question

I have the two objects. A and B.

A

{
   "beta" : {
     "value": null,
     "error" : null
   },
   "hamma" : {
     "value": null,
     "error" : null
   },
   "zerta" : {
     "value": null,
     "error" : null
   },
   "mozes" : 5
}

B

{
   "beta" : 5,
   "hamma" : 2
}

How do I can loop through the A keys, compare it with the B object and update the values of the existing keys in the A object via Lodash? Maybe there is exists some nice way? I tried to use "assing, assignWith" but looks like I haven't understood how it works.

The result should looks like that:

{
   "beta" : {
     "value": 5,
     "error" : null
   },
   "hamma" : {
     "value": 2,
     "error" : null
   },
   "zerta" : {
     "value": null,
     "error" : null
   },
   "mozes" : 5
}

Thanks for any information.

I have resolved this solution via native js by that way but I want to know how can I do it via Lodash.

export function mapServerModelToStateValues(state, serverModel) {
    let updatedState = {};
    const serverModelKeyList = Object.keys(serverModel);

    Object.keys(state).forEach(stateKey => {

        serverModelKeyList.forEach(modelKey => {
            if ( modelKey === stateKey ) {
                updatedState[ stateKey ] = {
                    ...state[ stateKey ],
                    value : serverModel[ modelKey ]
                }
            }
        });
    });

    console.log(updatedState);
}

Answer 1

You can use _.mergeWith lodash method and pass custom function.

 var a = {"beta":{"value":null,"error":null},"hamma":{"value":null,"error":null},"zerta":{"value":null,"error":null},"mozes":5} var b = {"beta":5,"hamma":2, "mozes": 123} _.mergeWith(a, b, function(aValue, bValue) { _.isPlainObject(aValue) ? aValue.value = bValue : aValue = bValue return aValue }) console.log(a) 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script> 

Answer 2

This will do the trick, notice that the result will have all the keys in the same value, error format

 const A = { "beta": { "value": null, "error": null }, "hamma": { "value": null, "error": null }, "zerta": { "value": null, "error": null }, "mozes": 5 } const B = { "beta": 5, "hamma": 2 } const C = _.mapValues(A, (value, key) => { return { ...value, value: B[key] || value.value } }); console.log(C) 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script> 

Answer 3

这是一个遍历B数组并使用set更新值的解决方案：

_.each(updates, (value, key) => _.set(data, `${key}.value`, value))

Answer 4

Map through the _keys from your second object to update the first object accordingly:

 // obj a const a = { beta: { value: null, error: null }, hamma: { value: null, error: null }, zerta: { value: null, error: null }, mozes: 5 }; // obj b const b = { beta: 5, hamma: 2 }; // map through the 'obj b' keys and update 'obj a' accordingly _.keys(b).map(key => { a[key].value = b[key]; }); // log obj a to the console console.log(a); 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script> 

Update: I would use the solution from @GruffBunny - the idea is similar to this one, but done much more elegantly using lodash.

Answer 5

You can use lodash#merge and lodash#mapValues to achieve this.

var result = _.merge({}, a, _.mapValues(b, value => ({ value })));

 var a = { "beta" : { "value": null, "error" : null }, "hamma" : { "value": null, "error" : null }, "zerta" : { "value": null, "error" : null }, "mozes" : 5 }; var b = { "beta" : 5, "hamma" : 2 }; var result = _.merge({}, a, _.mapValues(b, value => ({ value }))); console.log(result); 

 .as-console-wrapper { min-height: 100%; top: 0; } 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>