trpc-cli

Turn any trpc router into a fully-functional, documented CLI.

Installation

npm install trpc-cli @trpc/server zod

Usage

// router.js
import * as trpcServer from '@trpc/server'
import {trpcCli} from 'trpc-cli'
import {z} from 'zod'

const trpc = trpcServer.initTRPC.create()

const appRouter = trpc.router({
  sum: trpc.procedure
    .input(
      z.object({
        left: z.number(),
        right: z.number(),
      }),
    )
    .mutation(({input}) => input.left + input.right),
  divide: trpc.procedure
    .input(
      z.object({
        left: z.number(),
        right: z.number().refine(n => n !== 0),
      }),
    )
    .query(({input}) => input.left / input.right),
})

const cli = trpcCli({router: appRouter})

cli.run()

Then run node router.js --help and you will see formatted help text for the sum and divide commands.

Commands:
  sum           
  divide        

Flags:
      --full-errors        Throw unedited raw errors rather than summarising to make more human-readable.
  -h, --help               Show help

Running node router.js sum --help and node router.js divide --help will show help text for the corresponding procedures:

sum

Usage:
  sum [flags...]

Flags:
  -h, --help                  Show help
      --left <number>         
      --right <number>

Features

Procedures can define meta value with description, usage and help props. Zod's describe method allows adding descriptions to individual flags.

const appRouter = trpc.router({
  divide: trpc.procedure
    .input(
      z.object({
        left: z.number().describe('The numerator of the division operator'),
        right: z.number().describe('The denominator of the division operator'),
      }),
    )
    .mutation(({input}) => input.left / input.right),
})

Limitations

• Only zod types are supported right now

Implementation

• cleye for parsing arguments before passing to trpc
• zod-to-json-schema to convert zod schemas to make them easier to recusive
• zod-validation-error to make bad inputs have readable error messages