Ways to incorporate additional parameters into an object

Question

Ways to incorporate additional parameters into an object

Is there a way to incorporate new parameters into objects during a foreach loop in JavaScript?

const data = [big data];
data.forEach(async e => {
    Object.assign(e, {newData: 'string'};
    console.log(e); //new parameter added
})
console.log(data); //new parameter not added, why not?

During the forEach loop, I am trying to add a new parameter to each object. When I log the objects after using Object.assign, I can see that the new parameter has been successfully added. However, once the iteration is complete and I log my array of objects again, none of them seem to have the new parameter. Can anyone explain why this might be happening?

javascript typescript

Answer 1

Answer №1

You made some mistakes in your code syntax such as missing commas and not using quotes around strings. Please see the solution below:

Update: If you want to add to an object, make sure to define the object (not a string) in an array.

const data = [{"big":true}, {"data":true}];
data.forEach(e => {
    Object.assign(e, {newData: 'string'});
    console.log(e); //added new parameter
});
console.log(data); //not added new parameter, why?

Update: You included "async" in your question within the forEach loop... Unfortunately, using async is not recommended for the forEach function. Instead, consider using the traditional for loop.

// Timeout
const timeout = (ms) => new Promise(resolve => setTimeout(resolve, ms));

// Run in an async function!
(async () => {
  // Your array of objects
  const data = [{"big":true}, {"data":true}];
  // Loop
  for(let i = 0; i < data.length; i++) {
      const e = data[i];
      // Sleep for 1 second
      await timeout(1000);
      // Assign
      Object.assign(e, {newData: 'string'});
      // Debug
      console.log(e);
  }
  // The result will be displayed after all
  // awaits from the loop are completed
  console.log("result", data);
})();

Answer 2

You made some mistakes in your code syntax such as missing commas and not using quotes around strings. Please see the solution below:

Update: If you want to add to an object, make sure to define the object (not a string) in an array.

const data = [{"big":true}, {"data":true}];
data.forEach(e => {
    Object.assign(e, {newData: 'string'});
    console.log(e); //added new parameter
});
console.log(data); //not added new parameter, why?

Update: You included "async" in your question within the forEach loop... Unfortunately, using async is not recommended for the forEach function. Instead, consider using the traditional for loop.

// Timeout
const timeout = (ms) => new Promise(resolve => setTimeout(resolve, ms));

// Run in an async function!
(async () => {
  // Your array of objects
  const data = [{"big":true}, {"data":true}];
  // Loop
  for(let i = 0; i < data.length; i++) {
      const e = data[i];
      // Sleep for 1 second
      await timeout(1000);
      // Assign
      Object.assign(e, {newData: 'string'});
      // Debug
      console.log(e);
  }
  // The result will be displayed after all
  // awaits from the loop are completed
  console.log("result", data);
})();

Answer 3

Answer №2

Utilizing Object.assign() generates a newly created object.

In situations where you aim to produce an array of fresh objects, consider utilizing the map function.

const info = ["important", "details"];
let freshArray = info.map(element => {
    return Object.assign({}, {updatedData: element});
});
console.log(freshArray);

Note: the clarity of your inquiry is crucial. If you require just one object from the array:

let finalResult = {}
const info = ["important", "details"];
info.forEach(item => {
    finalResult[item] = 'information';
});
console.log(finalResult);

Answer 4

Utilizing Object.assign() generates a newly created object.

In situations where you aim to produce an array of fresh objects, consider utilizing the map function.

const info = ["important", "details"];
let freshArray = info.map(element => {
    return Object.assign({}, {updatedData: element});
});
console.log(freshArray);

Note: the clarity of your inquiry is crucial. If you require just one object from the array:

let finalResult = {}
const info = ["important", "details"];
info.forEach(item => {
    finalResult[item] = 'information';
});
console.log(finalResult);

Ways to incorporate additional parameters into an object

Answer №1

Answer №2

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