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typescriptnode-modulesloopbackjsloopback4

Is it recommended to publish source files for TypeScript node modules?

I noticed some TypeScript node modules (e.g loopback-next/packages) publish their source files with the node module. Is there a particular reason for this or is it just unnecessarily increasing the size of the module?

Solution

  • To start with a credible source: TypeScript Publishing guide only considers bundling of declaration files with the compiled .js files, no inclusion of .ts files.

    Being no contributor, I could imagine two reasons for package @loopback/authentication:

    1. Source Maps and debugging support (most likely)
    2. usage as some kind of source package 1

    1. Source Maps and debugging support

    The package authors might include source maps for debugging support, which reference/map to original .ts files in src. That way, those original sources need to be also distributed. E.g. authentication.component.js.map:

    "sources": ["../src/authentication.component.ts"],

    Side note: The sourcemap "spec" would also provide a sourcesContent field to support self contained source maps.

    2. Source package

    As an alternative to precompiled files, the package offers to be not opinionated concerning the build target. So a client app project can make use of its bundler and transpile the library in a specific target format itself. For example, if you support a) Electron and b) a wide variety of browsers, you don't need extra polyfills and transformations for the Electron renderer build.

    1 RFC: Source Packages #4092 ; see also 2, 3 (React biased)