Announcing TypeScript 3.9
IMO, until TypeScript gets the following features, it&#x27;s not worth using:<p>- Native TypeScript runtime interpreter in Deno (TypeScript alternative to Node.js).<p>- Native TypeScript runtime interpreter in all major browsers.<p>- At least 20% performance improvement over plain JavaScript.<p>The build step has to go away because:<p>- Source maps are unreliable, bulky, slow and add too much complexity for some environments; many environments fail at using them correctly and this can make it difficult to debug code. Being forced to debug ugly transpiled JavaScript is unacceptable and should never happen.<p>- It&#x27;s slow to work with. TypeScript often claims to be &#x27;scalable&#x27; but reality is that large projects often take multiple minutes to build for every change. There are no good incremental build solutions which also do proper type checking. There is no runtime type checking.<p>Native browser support is also essential. The bundling step makes in infeasible to freely mix and match modules written in the two languages in a way which is debuggable.<p>Microsoft should look into Adobe Flash&#x27;s ActionScript 3 migration from ActionScript 2 for inspiration (both based on ECMAScript spec BTW, just like JavaScript&#x2F;TypeScript).
I remember ActionScript 3 clearly because it was able to deliver a 40% speedup AND runtime type checking...<p>In spite of these huge benefits, I remember that some developers were still hesitant to switch to ActionScript 3! This new generation of developers has clearly lost its ability for critical thinking - I find the current complete lack of resistance to TS is very strange.<p>There are a lot more reasons to resist JS to TS migration compared to AS2 to AS3 migration.<p>I remember in AS2, most people were not declaring types in their code (even though there was support for compile-time type checking). Only in AS3 people started adding Type annotations to their code.