Creating a custom type for accepted arguments in a Typescript method

Question

Creating a custom type for accepted arguments in a Typescript method

Below is the structure of a method I have:

const a = function (...args: any[]) {
  console.log(args);
}

In this function, the type of args is any[]. I am looking to create a specific type for the array of arguments accepted by this method in Typescript. How can I achieve creating a specific type for the arguments accepted by this method? NOTE: The function a can accept various types of arguments such as

a(1, 2, 4, 5, 'asgasg', 124.52, { name: 'sparsh' });

I am aiming to define a specific type for the arguments allowed by the method in Typescript.

javascript typescript typescript-generics

Answer 1

Answer №1

If you need a specialized data type, you can define it yourself:

type myType = string | number

Here's an example of how you can use this custom type in a scenario:

type Person = {
  name: string;
}

type myType = string | number | Person;

function myFunction(...args: myType[]){}

Answer 2

If you need a specialized data type, you can define it yourself:

type myType = string | number

Here's an example of how you can use this custom type in a scenario:

type Person = {
  name: string;
}

type myType = string | number | Person;

function myFunction(...args: myType[]){}

Answer 3

Answer №2

Instead of using any[], consider utilizing unknown[].
By using unknown[], you can pass any type of arguments without disabling type checking for property access. For instance:

const a = function (...args: unknown[]) {
  console.log(args);
// console.log(args[0].toString); //disallowed by type checking 
  if(typeof args[0] === 'number') console.log(args[0].toFixed()) //allowed
}

a(2,3,4,5,6,7,"asds"); //ok

Answer 4

Instead of using any[], consider utilizing unknown[].
By using unknown[], you can pass any type of arguments without disabling type checking for property access. For instance:

const a = function (...args: unknown[]) {
  console.log(args);
// console.log(args[0].toString); //disallowed by type checking 
  if(typeof args[0] === 'number') console.log(args[0].toFixed()) //allowed
}

a(2,3,4,5,6,7,"asds"); //ok

Creating a custom type for accepted arguments in a Typescript method

Answer №1

Answer №2

Similar questions

Transfer the layout from one HTML file to multiple others without the need to retype the code

Having trouble with the Three.js OBJ loader in CodePen?

Adding HTML content to routes in ExpressOrEnhancing routes

ng-if is executed prior to the specified time

What is a regex with a touch of greed in its capture

Error: Unexpected identifier in jQuery ajax line

Updating Arrays in Node.js isn't happening as expected

What steps can I take to resolve the issue of the "self signed certificate in certificate chain" error while trying to install plugins on VS Code?

What is the correct way to include a new property in the MUI Link component using TypeScript?

Image failed to load

Communication between the content script and background page in a chrome extension is not functioning correctly as intended

Prevent tooltip text from appearing when a button is disabled in an angular application

Tips for setting up OpenLayers demonstrations on a personal server?

Coding in PHP, JavaScript, and HTML allows builders

Map failing to refresh

The state may be modified, but the component remains unchanged

Can the ValidationPipe be utilized with a whiteList on the response body?

Exploring the possibilities of reading and writing data in localStorage?

The circular reference error in Typescript occurs when a class extends a value that is either undefined, not a constructor,

There is an issue with the JSON format being received by fetch in JS when using json_encode in php