Javascript search array of lists of arrays

user_15087559 0
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I have a list of items I need to loop thru. I need to search if an array of items contains an array of items. This is the array, first value is timestamp, second is a count:

const i = [
    [1614719782079, 1],
    [1614719782085, 1],
    [1614719782091, 2],
    [1614719782096, 2],
]

And I have a forEach loop that goes thru all this data from my backend and I need to check if the timestamp exists in the array(the first value) and if it does, add to the second value of the array(count). This is an example data from backend:

  const mockData = [
    {
      ...someData,
      details: {
        eventTimestamp: 1614719782079, 
        equipmentId: 5,
        otherUselessData...
      }
    },
    {
      ...someData,
      details: {
        eventTimestamp: 1614719782079, 
        equipmentId: 5,
        otherUselessData...
      }
    }
  ]

Basically if eventTimestamp in the mockData exists in the i, then increment the second value in that array. PS dont ask about the horrible structure of the this data lol. This is all I have to work with

javascript
3 Answers

Following code should do the trick:

mockData.forEach(mock => {
  const el = i.find(e => e[0] === mock.details.eventTimestamp);
  if(el) {
    el[1]++
  }
})
user_29046780

Here is a possible solution:

  1. Create a Map of the elements of i where the first item is the key and the second is the value
  2. Iterate over mockData, and in each iteration, if the eventTimestamp is in this map, increment its value
  3. In the end, update i to the entries of this map

let i = [
    [1614719782079, 1],
    [1614719782085, 1],
    [1614719782091, 2],
    [1614719782096, 2],
];
const mockData = [
    { details: { eventTimestamp: 1614719782079, equipmentId: 5 } },
    { details: { eventTimestamp: 1614719782079, equipmentId: 5 } }
];

const updateTimestampCounts = (arr=[]) => {
  const map = new Map();
  i.forEach(([ timestamp, count ]) => map.set(timestamp, count));

  arr.forEach(({ details={} }) => {
    const { eventTimestamp } = details;
    const count = map.get(eventTimestamp);
    if(count) map.set(eventTimestamp, count+1);
  });
  
  i = [...map.entries()];
}

updateTimestampCounts(mockData)
console.log(i);

user_74863130

here is my edited solution, sorry , didnt understand it in first time

const i = [
    [1614719782079, 1],
    [1614719782085, 1],
    [1614719782091, 2],
    [1614719782096, 2],
]

const mockData = [
    {
      details: {
        eventTimestamp: 1614719782079, 
        equipmentId: 5,
      }
    },
    {
      details: {
        eventTimestamp: 1614719782079, 
        equipmentId: 5,
        count: 1,
      }
    }
  ]
  
mockData.forEach(mock => {
  const el = i.find(e => e[0] === mock.details.eventTimestamp);
  if(el) {
    el[1]++
  }
})
  console.log(i)

user_87732720
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