Getting Global variable into a Typescript file

Getting Global variable into a TypeScript file

When working with TypeScript, you may come across situations where you need to access a global variable from within a TypeScript file. While TypeScript provides a way to define global variables, accessing them directly can be a bit tricky. In this blog post, we will explore different solutions to get a global variable into a TypeScript file.

Solution 1: Using the ‘declare’ keyword

The ‘declare’ keyword in TypeScript is used to tell the compiler about the existence of an external variable or object. By using the ‘declare’ keyword, we can access global variables in our TypeScript file.

Here’s an example:

declare const globalVariable: string;

console.log(globalVariable); // Access the global variable

In the above code snippet, we use the ‘declare’ keyword to inform TypeScript about the existence of the global variable ‘globalVariable’. We can then access this variable just like any other variable in our TypeScript file.

Solution 2: Using the ‘window’ object

In JavaScript, global variables are attached to the ‘window’ object. TypeScript allows us to access global variables by using the ‘window’ object.

Here’s an example:

console.log(window.globalVariable); // Access the global variable

In the above code snippet, we access the global variable ‘globalVariable’ by prefixing it with the ‘window’ object. This allows TypeScript to recognize the global variable and access its value.

Solution 3: Using a module

If you have a global variable that needs to be accessed across multiple TypeScript files, you can create a separate module to encapsulate the variable.

Here’s an example:

globalVariable.ts

export const globalVariable: string = 'Hello, world!';

main.ts

import { globalVariable } from './globalVariable';

console.log(globalVariable); // Access the global variable

In the above code snippet, we define the global variable ‘globalVariable’ in a separate module called ‘globalVariable.ts’. We then import this variable into our main TypeScript file and access its value.

These are three different solutions to get a global variable into a TypeScript file. Depending on your specific use case, you can choose the solution that best fits your needs.

Remember, when working with global variables in TypeScript, it’s important to ensure that the variable is properly declared or accessible through the ‘window’ object. This will help TypeScript recognize and handle the global variable correctly.

Happy coding!