[英]Plain JS or Lodash - replace object values with values from other object
I have two objects: 我有两个对象:
let first = {
a: 'John',
b: 22,
c: 'example'
}
let second = {
b: 55,
d: 'demo'
}
I want to replace only already existing items from second object to first one. 我只想将已经存在的项目从第二个对象替换为第一个。 Result should look like this (so only b item should be changed, and new d item ignored):
结果应如下所示(因此仅应更改b项,而忽略新的d项):
{
a: 'John',
b: 55, // changed
c: 'example'
}
Merge will not work because it will add also new item. 合并将不起作用,因为它还会添加新项目。 I can use foreach but I believe that there should be shorted answer for this.
我可以使用foreach,但我认为应该对此做一个简短的回答。 I'm already using lodash in my project so I can use function from there, but I cannot find any for this purpose.
我已经在我的项目中使用lodash,因此可以从那里使用功能,但是我找不到用于此目的的任何功能。 Is there any?
有没有?
如果使用ES6,则可以使用它
let merge = { ...first, ..._.pick(second, Object.keys(first)) }
You can use a loop over the keys in the second array. 您可以在第二个数组中的键上使用循环。 For any keys that exist in the first, overwrite the value.
对于第一个中存在的任何键,请覆盖该值。
let first = { a: 'John', b: 22, c: 'example' } let second = { b: 55, d: 'demo' } for (const k in second) { if (k in first) { first[k] = second[k]; } } console.log(first);
With lodash you could do something like this with _.merge
, _.pick
and _.keys
: 使用lodash,您可以使用
_.merge
, _.pick
和_.keys
:
let first = { a: 'John', b: 22, c: 'example' }, second = { b: 55, d: 'demo' } let result = _.merge(first, _.pick(second, _.keys(first))) console.log(result)
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>
With ES6 you can use Object.keys and then Array.forEach on a new object like this: 使用ES6,您可以在新对象上使用Object.keys和Array.forEach ,如下所示:
let first = { a: 'John', b: 22, c: 'example' }, second = { b: 55, d: 'demo' }, result = new Object(null) Object.keys(first).forEach(k => result[k] = second[k] || first[k]) console.log(result)
This assumes you do not want to mutate
any of the objects. 假设您不想
mutate
任何对象。 IF you do not care: 如果您不在乎:
let first = { a: 'John', b: 22, c: 'example' }, second = { b: 55, d: 'demo' } Object.keys(first).forEach(k => first[k] = second[k] || first[k]) console.log(first)
You want to update the values of the 您要更新
intersection
路口
of the properties. 属性。
So basically something like: 所以基本上像这样:
Object.keys(a).forEach(prop => if(b.hasOwnProperty(prop)) a[prop] = b[prop]))
Or 要么
_.intersection(Object.keys(a), Object.keys(b)).forEach(prop => a[prop] = b[prop])
let first = { a: 'John', b: 22, c: 'example' } let second = { b: 55, d: 'demo' } Object.keys(second).forEach(function(key,index){ if (first.hasOwnProperty(key)) { first[key]=second[key]; } }); console.log(first);
With Lodash two functions MergeWith and Pick 使用Lodash的两个功能MergeWith和Pick
var a = {
a: 'John',
b: 22,
f:[11,22,2],
d: {a:1,b:2,c:0},
c: 'example'
}
var b = {
b: 55,
f:[3],
d: {c:1,b:11},
}
function mergeObjects(a,b){
let common = _.pick(b, Object.keys(a));
return _.mergeWith(a, common, customizer)
}
function customizer(objValue, srcValue) {
if (_.isArray(objValue)) {
return objValue.concat(srcValue);
}
if(_.isObject(objValue)) {
return mergeObjects(objValue,srcValue)
}
}
mergeObjects(a,b)
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