What the Go-powered compiler means for your full-stack JavaScript projects, and how to upgrade without a headache
Previously I would fire off the type-checker in my next.js project and go off for a coffee break. But with Typescript 7.0 I could be out of excuses!
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The TLDR
TypeScript 7.0 doesn’t introduce any exciting new features but does bring a native compiler and tooling written in Go. According to Microsoft it can make full builds up to 12x faster, with some benchmarks showing the VS Code code base went from 125.7s to 10.6s. This is an exciting update to TypeScript.
What has changed
Parallel builds — Parsing, type checking and emission can be done in parallel using the new --builders flag. You can also disable this using the --singleThreaded flag.
Watch mode — Has been rewritten to use a Go version of parcel’s file watcher.
Default values —strict is on, module is esnext, rootDir is ./, and types is [].
Deprecated options have become errors. Any options that were deprecated in 6.0 are not supported in 7.0.
The real upgrade risk is toolchain compatibility, not syntax. Testing TypeScript 7 on a CI branch first shows whether faster builds outweigh framework and compiler API limitations.
The new empty default for types looks like the change most likely to surprise people, since projects that relied on implicit @types inclusion will suddenly miss globals for tests or Node. Before upgrading I would run the build on a branch and…
