If -allowJs gave you decent results and you want to write a better definition file yourself, you can combine -allowJs with -declaration to see TypeScript's 'best guess' at the types of the library.

TypeScript will recognize things like ES5-style classes and JSDoc comments in these files, but may get tripped up if the library initializes itself in a weird way. js file in your compilation along with the -allowJs setting to see if this gives you good enough type information. TypeScript now supports the -allowJs flag and will make more JS-based inferences in. d.ts files this will have slightly more definitions than DefinitelyTyped.Ī few modules are also shipping their own definitions as part of their NPM distribution, so also see if that's the case before trying to write your own. You should also check TypeSearch ( ) which is a search engine for NPM-published. d.ts files and it's very likely the thing you're using is already there. This is a community repo full of literally thousands of. Maybe It Exists AlreadyĪlways check DefinitelyTyped ( ) first. Let's review the options, in roughly descending order of desirability.

There are a few options available for you depending on the library in question, how it's written, and what level of accuracy you're looking for.

Online typescript compiler