The Go Era: What Actually Matters in TypeScript 7.0 (Beyond the 10x Speedup)

Short summary

TypeScript 7.0 ships a native Go port delivering 8x-12x build speedups, but the real story is aggressive ecosystem modernization. The team chose Go over Rust for bug-for-bug compatibility, GC alignment with JS memory models, and faster shipping. Breaking changes include killing ES5 target, dropping legacy module systems (AMD/UMD/SystemJS), defaulting strict to true, removing baseUrl, isolating global types, and banning legacy import assertions.

• •Go port chosen over Rust for bug-for-bug compatibility and GC alignment with JS
• •ES5 target, legacy modules, downlevelIteration, and baseUrl all removed
• •strict mode and esnext module resolution now defaults; global types isolated by default

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