The definition files generated by the TypeScript compiler are indeed mostly a repeat of the code you wrote but with some notable differences: They don’t contain implementation, only declarations They only contain publicly accessible types The use case for these declaration files is for distributing libraries. You can distribute a library without the original TypeScript … Read more
You are right – declaration:true implies that only for each given .ts file tsc generates and copies a corresponding .d.ts output file to the build directory (in addition to .js and .map if applicable). So tsc will not copy your custom types.d.ts file to the output directory. Basically .d.ts files are seen as untouchable input … Read more
The “d.ts” file is used to provide typescript type information about an API that’s written in JavaScript. The idea is that you’re using something like jQuery or underscore, an existing javascript library. You want to consume those from your typescript code. Rather than rewriting jquery or underscore or whatever in typescript, you can instead write … Read more