Locate a specific item within an array using TypeScript

Question

Locate a specific item within an array using TypeScript

Looking for a more efficient solution to retrieve data from a collection in Typescript. The data is structured as follows:

myData:
{
  Id: string,
  Name: string,
  Address: string
  Salary: number
  phone: number
}

We have approximately 500 records, each with a unique ID. These records are displayed in a table showing only the ID and Name with checkboxes for each row.

When certain checkboxes are selected, I need to retrieve corresponding data by iterating through the list and taking action.

var selected: ImyData[];
for(var d in data)
{
  if(d.id == myId)
  {
    this.selected.id = d.id;
    this.selected.address = d.address
    this.selected.salary = d.salary
    return;
   }
 }

The current approach checks every element in the collection, which is not performance-effective. Any suggestions on how to improve efficiency in Typescript?

javascript typescript foreach

Answer 1

Answer №1

If you want to optimize your item lookup process in Javascript, consider creating a "dictionary" data structure (also known as assoc array, hashtable, or map). This allows for constant lookup time - O(1).

var selected = allItems[id];

You can initialize your dictionary using a for loop. This initialization only needs to be done once, and subsequent lookups will be very fast as they do not require a for loop.

Here is an example:

//Initialization, perform this step once!
var initObjects = [{ id: "id1", name:"name1" }, { id: "id2", name:"name2" }]

var dict = {};

for (i = 0; i < initObjects.length; i++) {
    var item = initObjects[i];
    dict[item.id] = item;
}

//Retrieving values. No loops needed! Constant lookup time - O(1)
console.log(dict["id2"])
console.log(dict["id1"])

(O(1) = constant lookup time independent of the size of your list. So the time taken to look up an item in a list with 100 or 1000000 items remains the same)

Answer 2

If you want to optimize your item lookup process in Javascript, consider creating a "dictionary" data structure (also known as assoc array, hashtable, or map). This allows for constant lookup time - O(1).

var selected = allItems[id];

You can initialize your dictionary using a for loop. This initialization only needs to be done once, and subsequent lookups will be very fast as they do not require a for loop.

Here is an example:

//Initialization, perform this step once!
var initObjects = [{ id: "id1", name:"name1" }, { id: "id2", name:"name2" }]

var dict = {};

for (i = 0; i < initObjects.length; i++) {
    var item = initObjects[i];
    dict[item.id] = item;
}

//Retrieving values. No loops needed! Constant lookup time - O(1)
console.log(dict["id2"])
console.log(dict["id1"])

(O(1) = constant lookup time independent of the size of your list. So the time taken to look up an item in a list with 100 or 1000000 items remains the same)

Answer 3

Answer №2

If you want to extract specific properties like "Id" and "Name" from an object, you can create a function that utilizes destructuring assignment within a for..of loop. This function will return the references to these properties if a match is found.

const myInfo = {
  Id: "001",
  Name: "John Doe",
  Age: "30",
  Occupation: "Engineer"
}

let targetId = "001";

const getIdAndName = (data, id) => {
  for (let {Id, Name} of [myInfo]) 
    if (Id === id) return {Id, Name}; 
  return `${id} not found in data`;
}

let result = getIdAndName(myInfo, targetId);

console.log(result);

Answer 4

If you want to extract specific properties like "Id" and "Name" from an object, you can create a function that utilizes destructuring assignment within a for..of loop. This function will return the references to these properties if a match is found.

const myInfo = {
  Id: "001",
  Name: "John Doe",
  Age: "30",
  Occupation: "Engineer"
}

let targetId = "001";

const getIdAndName = (data, id) => {
  for (let {Id, Name} of [myInfo]) 
    if (Id === id) return {Id, Name}; 
  return `${id} not found in data`;
}

let result = getIdAndName(myInfo, targetId);

console.log(result);

Locate a specific item within an array using TypeScript

Answer №1

Answer №2

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