Contrasting Map and Record: Understanding the best use cases for each

Question

Contrasting Map and Record: Understanding the best use cases for each

As I attempt to translate Java code using Maps into Typescript, it became apparent that using Maps in Typescript did not align with the interface I was working on. Instead, I discovered Records as a suitable alternative that closely resembles Java's Maps.

The key question I have is: when should I opt for Typescript's Maps over Records, and vice versa?

What are the distinct functionalities of each?

viewMappings: Record<string, String[]>;
viewMappings: Map<String, String[]>;

For instance,

I presumed these two approaches would behave similarly within my State interface, but they turned out to be quite different. I am seeking detailed documentation on the disparities between the two options.

javascript typescript

Answer 1

Answer №1

When it comes to defining record in programming:

type Record<K extends keyof any, T> = {
    [P in K]: T;
}

It's important to note that while Map is a built-in data structure in JavaScript ES6, a Record serves as a way to indicate that an object will function as a key-value map with a specific data type. Records are essentially plain objects created using {}. On the other hand, the Map object has distinct features outlined here and must be instantiated using new Map().

Answer 2

When it comes to defining record in programming:

type Record<K extends keyof any, T> = {
    [P in K]: T;
}

It's important to note that while Map is a built-in data structure in JavaScript ES6, a Record serves as a way to indicate that an object will function as a key-value map with a specific data type. Records are essentially plain objects created using {}. On the other hand, the Map object has distinct features outlined here and must be instantiated using new Map().

Answer 3

Answer №2

One key distinction for me is that when using a Record, a key lookup will not potentially return undefined. This streamlines my code by eliminating the need to account for missing keys.

Answer 4

One key distinction for me is that when using a Record, a key lookup will not potentially return undefined. This streamlines my code by eliminating the need to account for missing keys.

Answer 5

Answer №3

There are numerous answers to this question, all correct, yet lacking any specific guidelines on when to use each.

Using a Record (or regular objects) is typically faster and a reliable choice for anything within your application's internal workings. This is especially true for scenarios where you have prior knowledge of the types of keys that will be present.

On the other hand, a Map proves superior when dealing with non-string keys such as numbers and objects. It also shines in handling user-input due to its ability to steer clear from prototype pollution issues.

Answer 6

There are numerous answers to this question, all correct, yet lacking any specific guidelines on when to use each.

Using a Record (or regular objects) is typically faster and a reliable choice for anything within your application's internal workings. This is especially true for scenarios where you have prior knowledge of the types of keys that will be present.

On the other hand, a Map proves superior when dealing with non-string keys such as numbers and objects. It also shines in handling user-input due to its ability to steer clear from prototype pollution issues.

Answer 7

Answer №4

For the TS question at hand, the correct response is:

`Record`

Record serves as a shorthand for { [P in K]: T }, where P should be a string (or a symbol). While other types can be used for P, they will ultimately be converted to a string through the built-in method toString().

const testObject = {};
const obj: Record<any, string> = {
  1: 'hello',
  2: 'world',
  [testObject]: 'test',
};

console.log(obj[1]) // 'hello'
console.log(obj['1']) // 'hello'

console.log(obj[testObject]) // 'test'
console.log(obj['[object Object]']) // 'test'
console.log(obj[[/* an empty array*/]]) // 'test'

`Map`

A map functions as a key-value storage system. It performs similarly to a regular object but allows any value to be used as the key.

const testObject = {};
const map = new Map<any, string>();
map.set(1, 'hello');
map.set(1, 'world');
map.set(testObject, 'test');

console.log(obj.get(1)) // 'hello'
console.log(obj.get('1')) // undefined

console.log(obj[testObject]) // 'test'
console.log(obj['[object Object]']) // undefined
console.log(obj[[/* an empty array*/]]) // undefined

Answer 8

For the TS question at hand, the correct response is:

`Record`

Record serves as a shorthand for { [P in K]: T }, where P should be a string (or a symbol). While other types can be used for P, they will ultimately be converted to a string through the built-in method toString().

const testObject = {};
const obj: Record<any, string> = {
  1: 'hello',
  2: 'world',
  [testObject]: 'test',
};

console.log(obj[1]) // 'hello'
console.log(obj['1']) // 'hello'

console.log(obj[testObject]) // 'test'
console.log(obj['[object Object]']) // 'test'
console.log(obj[[/* an empty array*/]]) // 'test'

`Map`

A map functions as a key-value storage system. It performs similarly to a regular object but allows any value to be used as the key.

const testObject = {};
const map = new Map<any, string>();
map.set(1, 'hello');
map.set(1, 'world');
map.set(testObject, 'test');

console.log(obj.get(1)) // 'hello'
console.log(obj.get('1')) // undefined

console.log(obj[testObject]) // 'test'
console.log(obj['[object Object]']) // undefined
console.log(obj[[/* an empty array*/]]) // undefined

Answer 9

Answer №5

Utilizing all values from enums K and T is necessary in order to create a reliable record. Consider enum A and enum B as examples of this concept. When using Record<A,B>, any changes made to the source values in either enum A or enum B will trigger an error during compilation, prompting you to update the Record accordingly.

Answer 10

Utilizing all values from enums K and T is necessary in order to create a reliable record. Consider enum A and enum B as examples of this concept. When using Record<A,B>, any changes made to the source values in either enum A or enum B will trigger an error during compilation, prompting you to update the Record accordingly.

Answer 11

Answer №6

Record is a TypeScript utility type, while Map is an ES6 data structure with predefined methods. One could argue that a Record acts as an interface, whereas a Map has the ability to implement a Record (I will confirm this and provide further details).

In general, accessing lists of keys, values, or entries is somewhat simpler when using a Map compared to a Record.

Answer 12

Record is a TypeScript utility type, while Map is an ES6 data structure with predefined methods. One could argue that a Record acts as an interface, whereas a Map has the ability to implement a Record (I will confirm this and provide further details).

In general, accessing lists of keys, values, or entries is somewhat simpler when using a Map compared to a Record.

Answer 13

Answer №7

Mapping: This element is utilized for associating a particular value with another value.

Recording: This function serves to match one type with another type.

Answer 14

Mapping: This element is utilized for associating a particular value with another value.

Recording: This function serves to match one type with another type.

Answer 15

Answer №8

In the world of programming, Map concept is available in both javascript and typescript, while record is only found in typescript.

Map serves as an alternative way for creating objects, focusing on dynamic data storage and retrieval. On the other hand, record provides the structure of the object, emphasizing structured data representation.

An example of Record:

type user = {
      id  : number,
      name : string
    }
type library = Record<string, [user]>
const pondylibray :library ={
      "bookid1" : [{
           id : 2142,
           name : "jetpack"
        },]
    }

An example of Map:

type user = {
    id  : number,
    name : string
}

const pondylibrary = new Map<string,[user]>()
pondylibrary.set("book2" ,[{id:2142 , name :"jetpack"}])

Answer 16

In the world of programming, Map concept is available in both javascript and typescript, while record is only found in typescript.

Map serves as an alternative way for creating objects, focusing on dynamic data storage and retrieval. On the other hand, record provides the structure of the object, emphasizing structured data representation.

An example of Record:

type user = {
      id  : number,
      name : string
    }
type library = Record<string, [user]>
const pondylibray :library ={
      "bookid1" : [{
           id : 2142,
           name : "jetpack"
        },]
    }

An example of Map:

type user = {
    id  : number,
    name : string
}

const pondylibrary = new Map<string,[user]>()
pondylibrary.set("book2" ,[{id:2142 , name :"jetpack"}])

Contrasting Map and Record: Understanding the best use cases for each

Answer №1

Answer №2

Answer №3

Answer №4

`Record`

`Map`

Answer №5

Answer №6

Answer №7

Answer №8

Similar questions

Retrieve HTML Node upon Mouse Click, regardless of whether it is an Element or not

When I switch to a different navigation system, the css class gets removed

The function .click() fails to execute upon page load, yet it functions successfully when utilized in the console

What are the steps for implementing TextfieldProps from Material UI Props in a React Application?

The Vue production build displays a blank page despite all assets being successfully loaded

Angular constantly looping due to $watchCollection being triggered repeatedly

Issue with integrating Google Spreadsheet as the data source for a Next.JS website: updates are not reflecting on the website pages

Angular Pagination: Present a collection of pages formatted to the size of A4 paper

Tips for customizing the timing of a Bootstrap modal's opening delay?

choosing a date range

Struggling to incorporate z-index for a tooltip component that overlaps in a project utilizing React, Tailwind, and DaisyUI

Can the title of a page be modified without using HTML?

Switch between links with jQuery

Enhanced Floating Elements with jQuery on WordPress

Error encountered: Difficulty rendering Vue 3 components within Google Apps Script

Creating an array with checkboxes alongside key values can be achieved by following these steps in JavaScript

Steps for initiating an Angular 4 project

Simulate axios request functions using the built-in node:test test runner

Determine the total value of NodeJS for a particular date by parsing through JSON data

When using Express, the node.js application is able to skip over conditional statements and proceed