Is it a beneficial strategy to remove object keys and assign new keys when iterating through thousands of objects in a loop?

Question

Is it a beneficial strategy to remove object keys and assign new keys when iterating through thousands of objects in a loop?

Consider the following array as an example:

For instance

 var a =[{name :"Adi", age:23},{name:"aman" ,age : 23},{name : rob,age:52}];

Is it better to delete the keys 'name' or assign them as undefined? Which approach is more efficient? Does using the delete operator take longer than setting the value as undefined during multiple iterations?

javascript typescript

Answer 1

Answer №1

The quickest method involves iterating through them using a basic for loop:

for (let i = 0; i < arr.length; i++) {
  const item = arr[i];
  if (item.hasOwnProperty('umra')) {
    item.age = item.umra;
    delete item.umra;
  }
  ...
}

If the amount of data to process is large, chunking the array and processing it with zero timeouts can help prevent blocking the main thread during a lengthy loop. It's recommended to run intermediate setTimeout or other asynchronous functions using ngZone.runOutsideAngular in Angular to avoid triggering change detection:

const CHUNK_LENGTH = 1000;

ngZone.runOutsideAngular(async () => {
  for (let i = 0; i < arr.length; i++) {
    if (i > 0 && !(i % CHUNK_LENGTH)) {
      // new chunk
      await null;
    }

    const item = arr[i];

    if (item.hasOwnProperty('umra')) {
      item.age = item.umra;
      delete item.umra;
    }
    // ...
  }

  return arr;
})
.then(arr => {
  // .then triggers change detection after runOutsideAngular
})

For smaller chunks, it may be more efficient to switch to utilizing raw for loops and setTimeout rather than promises due to their overhead.

Tasks that are computationally intensive should ideally be carried out in web workers. However, in this scenario where there isn't a significant amount of computation and the same number of loop cycles need to be performed after receiving results from a web worker, utilizing web workers may not be necessary.

To optimize the process, it's advisable to reevaluate the necessity of processing objects received from API requests. If substantial processing is required, consider revising the API implementation.

Answer 2

The quickest method involves iterating through them using a basic for loop:

for (let i = 0; i < arr.length; i++) {
  const item = arr[i];
  if (item.hasOwnProperty('umra')) {
    item.age = item.umra;
    delete item.umra;
  }
  ...
}

If the amount of data to process is large, chunking the array and processing it with zero timeouts can help prevent blocking the main thread during a lengthy loop. It's recommended to run intermediate setTimeout or other asynchronous functions using ngZone.runOutsideAngular in Angular to avoid triggering change detection:

const CHUNK_LENGTH = 1000;

ngZone.runOutsideAngular(async () => {
  for (let i = 0; i < arr.length; i++) {
    if (i > 0 && !(i % CHUNK_LENGTH)) {
      // new chunk
      await null;
    }

    const item = arr[i];

    if (item.hasOwnProperty('umra')) {
      item.age = item.umra;
      delete item.umra;
    }
    // ...
  }

  return arr;
})
.then(arr => {
  // .then triggers change detection after runOutsideAngular
})

For smaller chunks, it may be more efficient to switch to utilizing raw for loops and setTimeout rather than promises due to their overhead.

Tasks that are computationally intensive should ideally be carried out in web workers. However, in this scenario where there isn't a significant amount of computation and the same number of loop cycles need to be performed after receiving results from a web worker, utilizing web workers may not be necessary.

To optimize the process, it's advisable to reevaluate the necessity of processing objects received from API requests. If substantial processing is required, consider revising the API implementation.

Answer 3

Answer №2

Utilize Web Workers for a Smooth UI Experience

var worker = run(function() {
  // Enhance efficiency by using key maps
  var keyMaps = {
    a: "x",
    b: "y",
    c: "z"
  };

  // Begin processing when objects are received
  onmessage = function(e) {
    objs = e.data;

    // Iterate through each object in the list of objects
    objs = objs.map(function(obj) {
      var o = {};

      // Iterate through each key in an object and map it accordingly
      for (k in obj) {
        o[keyMaps[k]] = obj[k]
      }

      return o;
    });

    // Notify the main program about the transformed data
 postMessage(objs);
    self.close();
  };
});

// Wrapper function to simplify Web Worker creation
function run(func) {
  return new Worker(URL.createObjectURL(new Blob([`(${func})()`]));
}

// Data received from API 
var objs = [{
    a: 1,
    b: 2,
    c: 3
  },
  {
    a: 4,
    b: 5,
    c: 6
  }
];

// Pass the received data to the worker
worker.postMessage(objs);

// Handle the output as needed
worker.onmessage = event => console.log(event.data);

Explanation:

Regardless of how the objects are structured, each property within each object must be processed. This results in a O(o * p) time complexity.
Traversing each object and its properties is necessary for data manipulation.
Implementing logic within a Web Worker is essential to prevent UI freeze.
Using key map simplifies coding compared to if-else or switch statements.

Answer 4

Utilize Web Workers for a Smooth UI Experience

var worker = run(function() {
  // Enhance efficiency by using key maps
  var keyMaps = {
    a: "x",
    b: "y",
    c: "z"
  };

  // Begin processing when objects are received
  onmessage = function(e) {
    objs = e.data;

    // Iterate through each object in the list of objects
    objs = objs.map(function(obj) {
      var o = {};

      // Iterate through each key in an object and map it accordingly
      for (k in obj) {
        o[keyMaps[k]] = obj[k]
      }

      return o;
    });

    // Notify the main program about the transformed data
 postMessage(objs);
    self.close();
  };
});

// Wrapper function to simplify Web Worker creation
function run(func) {
  return new Worker(URL.createObjectURL(new Blob([`(${func})()`]));
}

// Data received from API 
var objs = [{
    a: 1,
    b: 2,
    c: 3
  },
  {
    a: 4,
    b: 5,
    c: 6
  }
];

// Pass the received data to the worker
worker.postMessage(objs);

// Handle the output as needed
worker.onmessage = event => console.log(event.data);

Explanation:

Regardless of how the objects are structured, each property within each object must be processed. This results in a O(o * p) time complexity.
Traversing each object and its properties is necessary for data manipulation.
Implementing logic within a Web Worker is essential to prevent UI freeze.
Using key map simplifies coding compared to if-else or switch statements.

Is it a beneficial strategy to remove object keys and assign new keys when iterating through thousands of objects in a loop?

Answer №1

Answer №2

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