Phil Nash

4 Steps from JavaScript to TypeScript

Migrate from JavaScript to TypeScript without the risky rewrite. This talk provides a practical, four-step blueprint for adopting it at your own pace.

4 Steps from JavaScript to TypeScript
#1about 4 minutes

Evaluating the pros and cons of TypeScript adoption

Consider the benefits of type safety and improved tooling against the costs of a learning curve and build overhead before migrating a project.

#2about 3 minutes

Step 1: Enable TypeScript type checking for JavaScript files

Use editor settings like `checkJs` or a `// @ts-check` comment to get immediate type feedback on your JavaScript code without any build changes.

#3about 5 minutes

Step 2: Introduce the TypeScript compiler with a minimal setup

Add TypeScript as a dependency and configure `tsconfig.json` with non-strict settings like `allowJs` to compile existing JavaScript without errors.

#4about 3 minutes

Step 3: Enable build-time type checking for JavaScript files

Activate `checkJs` in your `tsconfig.json` to enforce type safety during the build and install necessary `@types` packages for dependencies.

#5about 4 minutes

Leverage JS Doc for type safety in JavaScript

Add types to your JavaScript project using JS Doc comments, allowing TypeScript to provide strong typing without converting files to `.ts`.

#6about 5 minutes

Step 4: Incrementally convert JavaScript files to TypeScript

Gradually rename `.js` files to `.ts` one at a time, updating syntax from CommonJS to ES Modules and adding explicit types as you go.

#7about 2 minutes

Recap of the four-step JavaScript to TypeScript migration

Review the complete migration path, from enabling editor checks and introducing the compiler to incrementally converting files and adding types.

#8about 2 minutes

How to convince your team to adopt TypeScript

Demonstrate the value of TypeScript by enabling `checkJs` on an existing project to reveal hidden type-related issues as a practical proof point.

Related jobs
Jobs that call for the skills explored in this talk.

Angular Developer

Picnic Technologies B.V.
Amsterdam, Netherlands

Intermediate
Senior

Featured Partners

From learning to earning

Jobs that call for the skills explored in this talk.

Rust and GoLang

Rust and GoLang

NHe4a GmbH
Karlsruhe, Germany

Remote
55-65K
Intermediate
Senior
Go
Rust