How to merge two arrays of objects in JavaScript and combine any objects that have the same name and-CodePudding

I have two JavaScript arrays:

let array1 = [{name:'jane', age: 20}, {name:'john', age: 30}];

let array2 = [{name:'bob', age: 50}, {name:'john', age: 25}];

I want the output to be:

let result = [{name:'jane', age: 20},{name:'bob', age: 50}, {name:'john', age: 55}];

The output array should combine john's age (30 25) since john is a duplicate.

How to merge two arrays of objects in JavaScript and combine any objects that have the same name and add the age.

CodePudding user response：

You can use 2 for loops to access the arrays and verify if is the same name, when is the same name, you change the old object to the new. like this:

let array1 = [{name:'jane', age: 20}, {name:'john', age: 30}];

let array2 = [{name:'bob', age: 50}, {name:'john', age: 25}];


for(let i in array1){
  for(let j in array2){
    if(array1[i].name == array2[j].name){
      let newAge = array2[j].age   array1[i].age
      array2[j] = {name: array2[j].name, age: newAge}
    } 
  }
}

console.log(array2);

CodePudding user response：

May be a little cryptic but it's fun:

Object.values(
  [...array1, ...array2].reduce((p, c) => ({...p, [c.name]: {...c, age: (p[c.name]?.age || 0)   c.age}}), {}),
);

CodePudding user response：

You can use grouping approach:

const array1 = [{name:'jane', age: 20}, {name:'john', age: 30}];
const array2 = [{name:'bob', age: 50}, {name:'john', age: 25}];

const grouped = [...array1, ...array2].reduce((acc, { name, age }) => {
   acc[name] ??= { name, age: 0 };
   acc[name].age  = age;
   
   return acc;
}, {});

const result = Object.values(grouped);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0 }