Formatting Prisma 2 schema programmatically in JavaScript (file and string)

[timleslie]

Problem

I am programmatically generating a prisma schema. Before I write it to a file I would like to ensure it is correctly formatted.

I currently achieve this with the following code:

const execa = require('execa');
const { resolveBinary } = require('@prisma/sdk');

const prismaSchema = (
  await execa(await resolveBinary('prisma-fmt'), ['format'], {
    env: { ...process.env, RUST_BACKTRACE: '1' },
    maxBuffer: 1000 * 1000 * 1000,
    input: `unformatted schema goes here`
  })
).stdout;

it would be nice if there was a way to achieve this without needing to execute a binary. Failing that, a sanctioned way to run the binary would be an improvement.

Suggested solution

I imagine a solution that looked something like:

const { formatSchema } = require('@prisma/sdk');

const prismaSchema = formatSchema('unformatted schema goes here');

Additional context

See discussion here

[Jolg42]

Hi @timleslie !

You can actually use it today (it is already there!) 😃

const { formatSchema } = require('@prisma/sdk');

// and then use it like
const output = await formatSchema({ schemaPath })

Under the hood this will call the prisma-fmt binary and return the output.

I will close this for now then. If you think it should be reopened let me know.

[timleslie]

This requires having the file written out to the file-system. Ideally I'd like to be able to do all this in memory before having to write to disk. In my use case I'm generating a collection of schemas and want to be able to take a hash of the (formatted) schema and look it up and only write to disk if it's a new schema. Writing to disk just to format the file so that I can check whether I need to write to disk is a bit of overkill. (I also realise that what I'm doing is perhaps outside of what could be considered regular usage of the library :-) )

ping @Jolg42

[Jolg42]

I think it's a valid use-case!

So since dev version 2.6.0-dev.16 you can now use it like:

await formatSchema({ 
	schema: `
		// My Prisma Schema
	`
})

or with a path

await formatSchema({ schemaPath: '..../schema.prisma' })

It will be part of the 2.6.0 release.

Enjoy 😉