prepending / appending to file (API bikeshedding)

[boneskull]

I'm using replace-in-files-cli (specifically, the programmatic API) to prepend a banner to a bunch of files.

There are myriad packages to do this sort of thing, but they either a) expect the data to be in package.json, b) are plugins for a task runner like grunt, c) unmaintained, or d) hopelessly broken and overengineered. If you have written a standalone tool to do this, please let me know!

This is what "prepend to file" looks like:

const replace = require('replace-in-files-cli/api');

// let's pretend top-level await works
await replace('/path/to/file', {
  find: [/^/], // <--------------------------
  replacement: '/* my awesome banner */'
});

Whereas "append to file" looks like this:

const replace = require('replace-in-files-cli/api');

// let's pretend top-level await works
await replace('/path/to/file', {
  find: [/$/g], // <------------------------
  replacement: '/* my awesome banner */'
});

This isn't quite obvious. I had to play around with regexes to arrive at "append", which works opposite of how I'd expect--I'd expect a banner after every line (which can be accomplished with /$/gm). Anyway.

• I'm thinking supporting append and prepend flags would be more user-friendly.
• But since it's not really a "replace" operation, maybe it's out-of-scope for this module?
• Providing sugar functions like append() or prepend() might be OK, except that a user may want to append/prepend and find/replace in a single operation--find accepts an array, after all.

[sindresorhus]

I didn't put much effort into the API, so it could definitely be improved.

How about adding a transform option that gives you the whole file and let you do whatever you want?

await replace('/path/to/file', {
  transform: (data, filePath) => `/* my awesome banner */\n${data}`
});