Protobuf .d.ts file overwritten at compile time?

[jbrjake]

I noticed that I couldn't compile a TypeScript project which depended on sketch-js, because it couldn't find interfaces exported by the proto:

node_modules/@datadog/sketches-js/dist/ddsketch/mapping/CubicallyInterpolatedMapping.d.ts:2:10 - error TS2305: Module '"../proto/compiled"' has no exported member 'IndexMapping'.

Looking in the node_modules of my project, I noticed that @datadog/sketches-js/dist/ddsketch/proto/compiled.d.ts contained only the lines:

export = $root;
declare var $root: $protobuf.Root;
import $protobuf = require("protobufjs/minimal");

...instead of the rich types you provide in that file in this git repo.

This looks similar to an issue in another project, which I found when googling the error message I was seeing:
https://github.com/cryptowatch/cw-sdk-node/issues/31

The problem is that tsc, when generating declarations, overrides the existing compiled.d.ts file in its zeal to declare types for compiled.js.

When I simply paste the real file into my node_modules, I'm able to successfully build my dependent project.

I looked for ways to avoid generating declarations for only one file, but couldn't find an option like that in tsc.

I believe this should be resolvable by appending a copy to the build script in package.json:

    "build": "yarn clean; tsc -p tsconfig.build.json; cp src/ddsketch/proto/compiled.d.ts dist/ddsketch/proto/compiled.d.ts",