Question

175

Find and replace object in array (based on id)

rated 0 times [ 177] [ 2] / answers: 1 / hits: 19708 / 5 Years ago, mon, february 25, 2019, 12:00:00

Got a bit of a puzzle here...I want to loop through allItems and return allItems but replace with any newItems that matches its id. How can I look for a match on id and then replace it with the correct object into the array?

const allItems = [

  {

    'id': 1,

    'category_id': 1,

    'text': 'old',

  },

  {

    'id': 2,

    'category_id': 1,

    'text': 'old'

  }

]



const newItems = [

  {

    'id': 1,

    'category_id': 1,

    'text': 'new',

    'more_info': 'abcd'

  },

  {

    'id': 2,

    'category_id': 1,

    'text': 'new',

    'more_info': 'abcd'

  }

]

What I tried so far:

for(let i = 0; i < allItems.length; i++) {

  if(newItems.indexOf(allItems[i].id) > -1){

    allItems[i] = newItems

  }

}

How can I get the position of the object in newItems and then replace it into allItems?

Answers

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brianaclaras

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4 Years ago

answered 5 Years ago andrewb · Accepted Answer

Use Array.map and Array.find():

const allItems = [

  { 'id': 1, 'category_id': 1, 'text': 'old' },

  { 'id': 2, 'category_id': 1, 'text': 'old' }

];



const newItems = [

  { 'id': 1, 'category_id': 1, 'text': 'new', 'more_info': 'abcd' },

  { 'id': 2, 'category_id': 1, 'text': 'new', 'more_info': 'abcd' }

];



const result = allItems.map(x => {

  const item = newItems.find(({ id }) => id === x.id);

  return item ? item : x;

});



console.log(result);

This can even be shortened by using a logical or to return the original item when the call to find returns undefined:

const result = allItems.map(x => newItems.find(({ id }) => id === x.id) || x);

Regarding your code, you can't use indexOf since it only compares primitive values or references in the case of arrays and objects.