Q:

Replacing objects in array

I have this javascript object:
var arr1 = [{id:'124',name:'qqq'}, 
           {id:'589',name:'www'}, 
           {id:'45',name:'eee'},
           {id:'567',name:'rrr'}]

var arr2 = [{id:'124',name:'ttt'}, 
           {id:'45',name:'yyy'}]

I need to replace objects in arr1 with items from arr2 with same id.
So here is the result I want to get:
var arr1 = [{id:'124',name:'ttt'}, 
           {id:'589',name:'www'}, 
           {id:'45',name:'yyy'},
           {id:'567',name:'rrr'}]

How can I implement it using javascript?

A:

You can use Array#map with Array#find.
arr1.map(obj => arr2.find(o => o.id === obj.id) || obj);

var arr1 = [{
    id: '124',
    name: 'qqq'
}, {
    id: '589',
    name: 'www'
}, {
    id: '45',
    name: 'eee'
}, {
    id: '567',
    name: 'rrr'
}];

var arr2 = [{
    id: '124',
    name: 'ttt'
}, {
    id: '45',
    name: 'yyy'
}];

var res = arr1.map(obj => arr2.find(o => o.id === obj.id) || obj);

console.log(res);

Here, arr2.find(o => o.id === obj.id) will return the element i.e. object from arr2 if the id is found in the arr2. If not, then the same element in arr1 i.e. obj is returned.

A:

What's wrong with Object.assign(target, source) ?

Arrays are still type object in Javascript, so using assign should still reassign any matching keys parsed by the operator as long as matching keys are found, right?

