CODEWITHSUNDEEP
javascript
lammy
lammy

Reputation: 467

Update array of objects with array of objects

My apologies if this has been addressed before, but I couldn't get it to work with anything I found.

Assume I have 2 arrays - arr1, arr2. I want to update the objects in arr1 if the the property id matches in arr1 and arr2. Objects that exist in arr2 but not in arr1 - meaning the property id does not exist in arr1 - should be pushed to arr1.

Example:

let arr1 = [
  {id: 0, name: "John"},
  {id: 1, name: "Sara"},
  {id: 2, name: "Domnic"},
  {id: 3, name: "Bravo"}
]

let arr2 = [
  {id: 0, name: "Mark"},
  {id: 4, name: "Sara"}
] 

# Expected Outcome

let outcome = [
  {id: 0, name: "Mark"},
  {id: 1, name: "Sara"},
  {id: 2, name: "Domnic"},
  {id: 3, name: "Bravo"},
  {id: 4, name: "Sara"}
]

Upvotes: 0

Views: 65

Answers (5)

Sven.hig
Sven.hig

Reputation: 4519

if you want to try something different you can use foreach and filter to achieve this 

let arr1 = [
  {id: 0, name: "John"},
  {id: 1, name: "Sara"},
  {id: 2, name: "Domnic"},
  {id: 3, name: "Bravo"}
]

let arr2 = [
  {id: 0, name: "Mark"},
  {id: 4, name: "Sara"}]


  arr1.forEach(x=>{
    arr2.forEach(y=>{
      if(x.id==y.id){
        x.name=y.name
      }
    })
  })
 arr2.filter((a)=>{if(!arr1.some(b=>a.id==b.id)) arr1.push(a)})


  console.log(arr1)

Upvotes: 0

Danziger
Danziger

Reputation: 21161

Assuming you want to mutate the objects in arr1 rather than creating new ones, one way to do it would be using for...of to iterate the objects in arr2 and then check if there's already an object with the same id in arr1 using Array.prototype.find():

  • If there is one, you mutate it with Object.assign.
  • Otherwise, push the new object to arr1:

const arr1 = [
  { id: 0, name: 'John' },
  { id: 1, name: 'Sara' },
  { id: 2, name: 'Domnic' },
  { id: 3, name: 'Bravo' },
];

const arr2 = [
  { id: 0, name: 'Mark', sometingElse: 123 },
  { id: 2, foo: 'bar' },
  { id: 4, name: 'Sara' },
];

for (const currentElement of arr2) {
  let previousElement = arr1.find(el => el.id === currentElement.id);
  
  if (previousElement) {
    Object.assign(previousElement, currentElement);
  } else {
    arr1.push(currentElement);
  }
}

console.log(arr1);
.as-console-wrapper {
  max-height: 100% !important;
}

Upvotes: 0

ABGR
ABGR

Reputation: 5205

You could do this:

 let arr1 = [
      {id: 0, name: "John"},
      {id: 1, name: "Sara"},
      {id: 2, name: "Domnic"},
      {id: 3, name: "Bravo"}
    ]

    let arr2 = [
      {id: 0, name: "Mark"},
      {id: 4, name: "Sara"}
    ] 
    
    var res = arr1.reduce((acc, elem)=>{
       var x = arr2.find(i=>i.id === elem.id);
       
       if(x){
          acc.push(x)
       }else{
         acc.push(elem)
       }
       return acc
    }, []);
    
    console.log(res)

Upvotes: 1

blex
blex

Reputation: 25634

You can use reduce and find for this:

const arr1 = [
  {id: 0, name: "John"},
  {id: 1, name: "Sara"},
  {id: 2, name: "Domnic"},
  {id: 3, name: "Bravo"}
];

const arr2 = [
  {id: 0, name: "Mark"},
  {id: 4, name: "Sara"}
];

arr2.reduce((res, item) => {
  const existingItem = res.find(x => x.id === item.id);
  if (existingItem) { existingItem.name = item.name; }
  else { res.push(item); }
  return res;
}, arr1);

console.log(arr1);

Upvotes: 1

Gershom Maes
Gershom Maes

Reputation: 8140

You should be able to use Array.prototype.find to sort this out!

let arr1 = [
  {id: 0, name: "John"},
  {id: 1, name: "Sara"},
  {id: 2, name: "Domnic"},
  {id: 3, name: "Bravo"}
];

let arr2 = [
  {id: 0, name: "Mark"},
  {id: 4, name: "Sara"}
];

let updateArrayOfObjects = (arr1, arr2) => {
  for (let obj of arr2) {
    let item = arr1.find(v => v.id === obj.id);
    if (item) item.name = obj.name;
    else      arr1.push({ ...obj });
  }
  return arr1;
};

console.log(updateArrayOfObjects(arr1, arr2));

Upvotes: -1

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