Tips for determining if a class has been declared in Typescript

When it comes to checking if a class (or any other element) exists in the global scope, Javascript offers a convenient method:

typeof SomeUndeclaredOne === 'undefined'

However, this approach doesn't translate well into TypeScript as it triggers a compilation error:

error TS2304: Cannot find name 'SomeUndeclaredOne'

Hence, my inquiry is: what is the simplest way to determine the presence of a class in TypeScript? I am seeking a universal solution that functions not only in browsers but also in different environments (such as node.js or others lacking a global object) and is compatible with prevalent module systems like ESModules, CommonJS, etc.

I appreciate any guidance you can provide. Thank you in advance.

typescript

Answer №1

To resolve the error, consider declaring the class using TypeScript.

declare class NewClassToDeclare {}
console.log(typeof NewClassToDeclare === "undefined")

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