service: fix handling of --option <value>

[alanpearce]

Running prettier --help shows options with their values separated with spaces.

Running prettierd with the options formatted as such doesn't work, but prettier doesn't differentiate between --opt=val and --opt val. Unfortunately my editor setup uses the space variety and isn't easy to change as it affects other formatting tools as well.

A better solution would be to somehow import prettier's option handling code, but I thought that might be a bit too much for this.

before:

bin/prettierd --tab-width 2 --stdin-filepath src/service.ts < src/service.ts # ❌
bin/prettierd --tab-width=2 --stdin-filepath src/service.ts < src/service.ts # ✅
bin/prettierd --stdin-filepath src/service.ts < src/service.ts # ✅
bin/prettierd src/service.ts < src/service.ts # ✅

after:

bin/prettierd --tab-width=2 --stdin-filepath src/service.ts < src/service.ts # ✅
bin/prettierd --tab-width 2 --stdin-filepath src/service.ts < src/service.ts # ✅
bin/prettierd --stdin-filepath src/service.ts < src/service.ts # ✅
bin/prettierd src/service.ts < src/service.ts # ✅

[fsouza]

I think the problem is that there are cases where this isn't true (some examples include --bracket-same-line and --single-quote), so it's hard to solve. We may need to actually use something that has the specific options and try to keep them in sync with prettier, which is a pain :(

[alanpearce]

I was playing around in the repl and got this out:

(await require("prettier").getSupportInfo()).options.filter(o => o.type === "boolean").map(o => o.name)

[
  'singleQuote',
  'bracketSpacing',
  'bracketSameLine',
  'singleAttributePerLine',
  'vueIndentScriptAndStyle',
  'semi',
  'experimentalTernaries',
  'jsxSingleQuote',
  'insertPragma',
  'requirePragma',
  'useTabs'
]

These are all the prettier options¹ that don't take an argument (some have o.default: true, meaning the argument would have a no- prefix, like --no-semi).

This seems like something that can be worked with, but the arguments could be different depending on the resolved prettier version, which wouldn't be a problem, except that we don't know the version until we've parsed the arguments :^).

Given how prettierd doesn't support prettierd file.ts, I'm more inclined to suggest that --stdin-filepath <filename> should be required, which would be a breaking change, but far simpler.

Footnotes

1. the prettier CLI has other arguments that don't take a value, but here we're calling the module ↩

[fsouza]

Hmm yeah I think that's an OK breaking change to make, as it simplifies things and makes prettierd command line interface compatible with prettier.

Do you want to give it a shot?

[alanpearce]

Sure, will do!

[alanpearce]

It's a shame iterators don't provide a peek() or prev() function; I had to use the ancient style of for loop :(

[fsouza]

do we still want this check?

[alanpearce]

Thanks for pointing that out. Made me realise I missed some edge cases.