Replacing objects in array

Question

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?

Answer 1

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.

Answer 2

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?