Set as executable files that are intended to be binaries

Search Terms

• mode
• binary
• executable
• package.json bin

Suggestion

Currently, the TypeScript compiler always generates files with the 644 mode. But some files are meant to be executable: they may start with #!/usr/bin/env node; they may be marked as bin in package.json; they may have an executable mode set on the .ts source; and so forth.

It’d be great if the TypeScript compiler would take any of the hints I mentioned above, figure that the file should be executable, and create the .js as so.

At least the TypeScript compiler doesn’t change the mode of existing .js files when overwriting them, so I can chmod once, and as long as never delete the file, it’ll have the right mode.

Use Cases

This is mostly for development and running the binary from the command-line directly. Once you install the package, npm puts the binary in the node_modules/.bin folder, npx picks it up, and all is good.

Examples

You’re working on a project that should provide a binary: src/my-binary.ts. You do one of the things I mentioned to indicate that the file should be executable. You run tsc, and the generated file at lib/my-binary.js is marked as +x. Then you can call the binary with lib/my-binary.js from the command-line and it works.

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

Start with the tsc flow that emits src/my-binary.ts as lib/my-binary.js, then investigate how output file modes are currently chosen. Done means defining and implementing a supported rule for recognizing intended binaries and verifying that the generated JavaScript is executable without changing existing behavior.