CODEWITHSUNDEEP
javascript
Cedric Hadjian
Cedric Hadjian

Reputation: 914

Pushing x number of array items to another array conditionally

I want to push x number of array items to another array with the condition that the maximum number of items that will be pushed be the difference of maxPushLimit (which is 720) and alreadyPushed (so if alreadyPushed is, say, 300, only 420 can be pushed)

Special conditions:


I wrote this code to achieve it: 
const array1 = [
  {
    id: 1,
    alreadyPushed: 500,
  },
  {
    id: 2,
    alreadyPushed: 600,
  },
  {
    id: 3,
    alreadyPushed: 700,
  },
  {
    id: 4,
    alreadyPushed: 720,
  },
];

const array2 = [];
for (let i = 1; i < 361; i++) {
  array2.push(i);
}

const maxPushLimit = 720;

let results = [];
let array2Index = 0;

for (let i = 0; i < array1.length; i++) {
  const array1Item = array1[i];
  const limit = maxPushLimit - array1Item.alreadyPushed;
  console.log(limit);

  if (limit <= 0) {
    continue;
  } else {
    array1Item.array2Items = array2.slice(array2Index, limit);
    array2Index += limit;
    results.push(array1Item);
  }
}

console.log(results);

Keep in mind that the order of alreadyPushed is not important (500, 600, 700, 720 are totally random)
I want the end result to look like this:

[
    {
      id: 1,
      alreadyPushed: 500,
      array2Items: {
          // 220 array2Items
      }
    },
    {
      id: 2,
      alreadyPushed: 600,
      array2Items: {
          // 120 array2Items
      }
    },
    {
      id: 3,
      alreadyPushed: 700,
      array2Items: {
          // 20 array2Items
      }
    },
];

What I'm getting:

[
  {
    id: 1,
    alreadyPushed: 500,
    array2Items: [
       // 220 array2Items
    ]
  },
  { id: 2, alreadyPushed: 600, array2Items: [] },
  { id: 3, alreadyPushed: 700, array2Items: [] }
]

Upvotes: 1

Views: 47

Answers (2)

trincot
trincot

Reputation: 350147

The problem is in this expression:

array2.slice(array2Index, limit);

The second argument should not be the size of the slice, but the ending index of the slice.

So change to:

array2.slice(array2Index, array2Index + limit);

Upvotes: 1

Alexander Wu
Alexander Wu

Reputation: 483

The problem is the slice operation. It should be array2.slice(array2Index, array2Index + limit);.

Upvotes: 1

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