Conditional copying properties and values from one array of objects to another

user_16449187 0
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Got two arrays of objects and my goal is to check if the value under property id from array1 matches the value under the property categoryId of array2. When find a match want to add the missing property amount to the relevant member of array1 or create a new array containing all the properties and values I need - id, name, amount

Here are the two arrays:

const array1 = [{
  id: 8,
  name: 'Online Shopping',
},
{
  id: 12,
  name: 'Subscriptions',
},
{
 id: 5,
  name: 'Patreon donations',
}]

and

const array2 = [
{
  expence: {
    amount: -66.66,
  },
  categoryId: 5,
},
{
  expence: {
    amount: 100018.85,
  },
  categoryId: 0,
},
{
  expence: {
    amount: -43340.9,
  },
  categoryId: 12,
},]

Tried to combine different approaches from answers to similar but simpler cases already posted in the community but didn't managed to make them work in my case.

javascript-objects arrays javascript
1 Answers

Loop through each item in array1, then loop through each item in array2 inside the loop and check whether the categoryId is equal to the id. 

const array1 = [{
    id: 8,
    name: 'Online Shopping',
  },
  {
    id: 12,
    name: 'Subscriptions',
  },
  {
    id: 5,
    name: 'Patreon donations',
  }
]
const array2 = [{
    expence: {
      amount: -66.66,
    },
    categoryId: 5,
  },
  {
    expence: {
      amount: 100018.85,
    },
    categoryId: 0,
  },
  {
    expence: {
      amount: -43340.9,
    },
    categoryId: 12,
  },
]

array1.forEach((e) => {
  array2.forEach((f) => {
    if (f.categoryId == e.id) {
      e.amount = f.expence.amount;
    }
  })
})
console.log(array1);

You can also make use of Array.filter to find the item where the categoryId is equal to the id:

const array1 = [{
    id: 8,
    name: 'Online Shopping',
  },
  {
    id: 12,
    name: 'Subscriptions',
  },
  {
    id: 5,
    name: 'Patreon donations',
  }
]
const array2 = [{
    expence: {
      amount: -66.66,
    },
    categoryId: 5,
  },
  {
    expence: {
      amount: 100018.85,
    },
    categoryId: 0,
  },
  {
    expence: {
      amount: -43340.9,
    },
    categoryId: 12,
  },
]

array1.forEach((e) => {
  var arr = array2.filter(f => f.categoryId == e.id);
  if(arr.length > 0) e.amount = arr[0].expence.amount;
})
console.log(array1);

user_142512210
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