Microsoft has announced its plans to develop a native TypeScript implementation based on Google's Go language, promising dramatic improvements in editor startup speed, build times, and memory usage. The initiative, announced on March 11, involves porting the TypeScript compiler, tools, and code base from JavaScript to Go, with the goal of delivering a feature-complete Go implementation of TypeScript by the end of 2025.

The TypeScript team expects to preview command-line type-checking in Go-based tsc by mid-2025, which will enable developers to experience the increased speed and responsiveness of the new implementation. According to Microsoft, developers who use Go-based TypeScript in the Visual Studio Code editor can expect an 8x improvement in project load times, instant comprehensive error listings across entire projects, and greater responsiveness for all language service operations.

The new TypeScript implementation will also support more advanced refactoring and deeper insights that were previously too expensive to compute. A demo video of the project is available, showcasing the potential of the new implementation. Microsoft expects developers to be "extremely excited" about this new development, as one of the most common pain points for users of the current, JavaScript-based TypeScript is that performance slows when it is used for large-scale apps.

Developers can already build and run the Go code from a new working repo, offered under the same Apache License 2 license as the existing TypeScript code base. The JavaScript code base will continue development into the 6.x series, with TypeScript 6.0 introducing some deprecations and breaking changes to align with the upcoming native code base. When the native code base has reached sufficient parity with the current TypeScript, Microsoft will release it as TypeScript 7.0.

While some projects may switch to TypeScript 7.0 upon release, others may depend on certain API features, legacy configurations, or other constraints that require the continued use of TypeScript 6.0. Microsoft has assured that the JavaScript code base will be maintained in the 6.x line until TypeScript 7.x reaches sufficient maturity and adoption, ensuring a smooth transition for developers.

The move to a Go-based implementation is a significant one, as it promises to address the performance issues that have plagued TypeScript users. By leveraging the strengths of Go, Microsoft aims to create a more scalable and efficient TypeScript implementation that can handle large code bases with ease. As the project progresses, developers can expect to see significant improvements in their workflow, making it easier to build and maintain complex applications.

The implications of this move are far-reaching, with potential benefits for the entire developer ecosystem. As TypeScript continues to grow in popularity, a more efficient and scalable implementation can only serve to further its adoption. With Microsoft's commitment to delivering a feature-complete Go implementation by the end of 2025, developers can look forward to a future where building and maintaining large-scale applications becomes faster, easier, and more efficient.