TypeScript tutorialLesson 37Free preview

TS in JS Projects

This lesson is part of TypeScript · All levels

Summary

Older JavaScript projects can benefit from type through JSDoc annotations and allowJs and checkJs options. With checkJs, TypeScript checks the type directly on the .js file without having to migrate it. This method provides some type safety with very minimal change.

Key points

AllowJs allows .js files to be compiled
CheckJs checks the type on the JS file
JSDoc uses @param, @returns, and @type

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