Merge two array of objects based on a key

Question

You can do it like this –

let arr1 = [
    { id: "abdc4051", date: "2017-01-24" },
    { id: "abdc4052", date: "2017-01-22" }
];

let arr2 = [
    { id: "abdc4051", name: "ab" },
    { id: "abdc4052", name: "abc" }
];

let arr3 = arr1.map((item, i) => Object.assign({}, item, arr2[i]));

console.log(arr3);

Use below code if arr1 and arr2 are in a different order:

let arr1 = [
  { id: "abdc4051", date: "2017-01-24" }, 
  { id: "abdc4052", date: "2017-01-22" }
];

let arr2 = [
  { id: "abdc4051", name: "ab" },
  { id: "abdc4052", name: "abc" }
];

let merged = [];

for(let i=0; i<arr1.length; i++) {
  merged.push({
   ...arr1[i], 
   ...(arr2.find((itmInner) => itmInner.id === arr1[i].id))}
  );
}

console.log(merged);

Use this if arr1 and arr2 are in a same order

let arr1 = [
  { id: "abdc4051", date: "2017-01-24" }, 
  { id: "abdc4052", date: "2017-01-22" }
];

let arr2 = [
  { id: "abdc4051", name: "ab" },
  { id: "abdc4052", name: "abc" }
];

let merged = [];

for(let i=0; i<arr1.length; i++) {
  merged.push({
   ...arr1[i], 
   ...arr2[i]
  });
}

console.log(merged);

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