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Positional parameters (#2)
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- Support positional parameters like `migra postgresql://a
psotgresql://b`
- Also support numbers
- Also support booleans
- `getInnerType` helper to more accurately inspect zod schemas
- reorganise src dir into separate files rather than one 400+ line
index.ts
- udpate calculator example to use positional parameters so `calculator
add 2 3` rather than `calculator add --left 2 --right 3`
- more hand-written docs on how flags and positional parameters work
- return `ignoredProcedures` instead of throwing when invalid
- add a validation test

---------

Co-authored-by: Misha Kaletsky <mmkal@users.noreply.github.com>
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mmkal and mmkal authored May 24, 2024
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226 changes: 175 additions & 51 deletions README.md
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@@ -1,10 +1,18 @@
# trpc-cli

Turn a [trpc](https://trpc.io) router into a type-safe, fully-functional, documented CLI.
Turn a [tRPC](https://trpc.io) router into a type-safe, fully-functional, documented CLI.

<!-- codegen:start {preset: markdownTOC} -->
- [Installation](#installation)
- [Usage](#usage)
- [Parameters and flags](#parameters-and-flags)
- [Positional parameters](#positional-parameters)
- [Flags](#flags)
- [Both](#both)
- [API docs](#api-docs)
- [trpcCli](#trpccli)
- [Params](#params)
- [Returns](#returns)
- [Calculator example](#calculator-example)
- [Output and lifecycle](#output-and-lifecycle)
- [Features and Limitations](#features-and-limitations)
Expand All @@ -17,6 +25,9 @@ Turn a [trpc](https://trpc.io) router into a type-safe, fully-functional, docume
- [Testing](#testing)
<!-- codegen:end -->

[![Build Status](https://github.com/mmkal/trpc-cli/actions/workflows/ci.yml/badge.svg)](https://github.com/mmkal/trpc-cli/actions/workflows/ci.yml/badge.svg)
[![npm](https://badgen.net/npm/v/trpc-cli)](https://www.npmjs.com/package/trpc-cli)

## Installation

```
Expand All @@ -35,8 +46,8 @@ const t = initTRPC.create()

export const router = t.router({
add: t.procedure
.input(z.object({a: z.number(), b: z.number()}))
.query(({input}) => input.a + input.b),
.input(z.object({left: z.number(), right: z.number()}))
.query(({input}) => input.left + input.right),
})
```

Expand All @@ -54,15 +65,139 @@ And that's it! Your tRPC router is now a CLI program with help text and input va

You can also pass an existing tRPC router that's primarily designed to be deployed as a server to it, in order to invoke your procedures directly, in development.

>Note that this library is still v0, so parts of the API may change slightly. The basic usage of `trpcCli({router}).run()` will remain though!
### Parameters and flags

CLI positional parameters and flags are derived from each procedure's input type. Inputs should use a `zod` object or tuple type for the procedure to be mapped to a CLI command.

#### Positional parameters

Positional parameters passed to the CLI can be declared with types representing strings, numbers or booleans:

```ts
t.router({
double: t.procedure
.input(z.number()) //
.query(({input}) => input * 2),
})
```

You can also use anything that accepts string, number, or boolean inputs, like `z.enum(['up', 'down'])`, `z.literal(123)`, `z.string().regex(/^\w+$/)` etc.

Multiple positional parameters can use a `z.tuple(...)` input type:

```ts
t.router({
add: t.procedure
.input(z.tuple([z.number(), z.number()]))
.query(({input}) => input[0] + input[1]),
})
```

Which is invoked like `path/to/cli add 2 3` (outputting `5`).

>Note: positional parameters can use `.optional()` or `.nullish()`, but not `.nullable()`.
>Note: positional parameters can be named using `.describe('name of parameter')`, but names can not include any special characters.
>Note: positional parameters are parsed based on the expected target type. Booleans must be written as `true` or `false`, spelled out. In most cases, though, you'd be better off using [flags](#flags) for boolean inputs.
#### Flags

`z.object(...)` inputs become flags (passed with `--foo bar` or `--foo=bar`) syntax. Values are accepted in either `--camelCase` or `--kebab-case`, and are parsed like in most CLI programs:

Strings:

- `z.object({foo: z.string()})` will map:
- `--foo bar` or `--foo=bar` to `{foo: 'bar'}`

Booleans:

- `z.object({foo: z.boolean()})` will map:
- `--foo` or `--foo=true` to `{foo: true}`
- `--foo=false` to `{foo: false}`

>Note: it's usually better to use `z.boolean().optional()` than `z.boolean()`, otherwise CLI users will have to pass in `--foo=false`.
Numbers:

- `z.object({foo: z.number()})` will map:
- `--foo 1` or `--foo=1` to `{foo: 1}`

Other types:
- `z.object({ foo: z.object({ bar: z.number() }) })` will parse inputs as JSON:
- `--foo '{"bar": 1}'` maps to `{foo: {bar: 1}}`

Unions and intersections should also work as expected, but please test them thoroughly, especially if they are deeply-nested.

#### Both

To use positional parameters _and_ flags, use a tuple with an object at the end:

```ts
t.router({
copy: t.procedure
.input(
z.tuple([
z.string().describe('source'),
z.string().describe('target'),
z.object({
mkdirp: z
.boolean()
.optional()
.describe("Ensure target's parent directory exists before copying"),
}),
]),
)
.mutation(async ({input: [source, target, opts]}) => {
if (opts.mkdirp) {
await fs.mkdir(path.dirname(target, {recursive: true}))
}
await fs.copyFile(source, target)
}),
})
```

You might use the above with a command like:

```
path/to/cli copy a.txt b.txt --mkdirp
```

>Note: object types for flags must appear _last_ in the `.input(...)` tuple, when being used with positional parameters. So `z.tuple([z.string(), z.object({mkdirp: z.boolean()}), z.string()])` would not be allowed.
Procedures with incompatible inputs will be returned in the `ignoredProcedures` property.

### API docs

<!-- codegen:start {preset: markdownFromJsdoc, source: src/index.ts, export: trpcCli} -->
#### [trpcCli](./src/index.ts#L27)

Run a trpc router as a CLI.

##### Params

|name |description |
|-------|-----------------------------------------------------------------------------------------|
|router |A trpc router |
|context|The context to use when calling the procedures - needed if your router requires a context|
|alias |A function that can be used to provide aliases for flags. |

##### Returns

A CLI object with a `run` method that can be called to run the CLI. The `run` method will parse the command line arguments, call the appropriate trpc procedure, log the result and exit the process. On error, it will log the error and exit with a non-zero exit code.
<!-- codegen:end -->

### Calculator example

Here's a more involved example, along with what it outputs:

<!-- codegen:start {preset: custom, require: tsx/cjs, source: ./readme-codegen.ts, export: dump, file: test/fixtures/calculator.ts} -->
<!-- hash:efe19a66f7467160525f69c8ce4daef3 -->
<!-- hash:ae42f01a6ea72021b5bc7f4823803c9f -->
```ts
import * as trpcServer from '@trpc/server'
import {TrpcCliMeta, trpcCli} from 'trpc-cli'
import {trpcCli, type TrpcCliMeta} from 'trpc-cli'
import {z} from 'zod'

const trpc = trpcServer.initTRPC.meta<TrpcCliMeta>().create()
Expand All @@ -73,37 +208,22 @@ const router = trpc.router({
description:
'Add two numbers. Use this if you and your friend both have apples, and you want to know how many apples there are in total.',
})
.input(
z.object({
left: z.number().describe('The first number'),
right: z.number().describe('The second number'),
}),
)
.query(({input}) => input.left + input.right),
.input(z.tuple([z.number(), z.number()]))
.query(({input}) => input[0] + input[1]),
subtract: trpc.procedure
.meta({
description:
'Subtract two numbers. Useful if you have a number and you want to make it smaller.',
})
.input(
z.object({
left: z.number().describe('The first number'),
right: z.number().describe('The second number'),
}),
)
.query(({input}) => input.left - input.right),
.input(z.tuple([z.number(), z.number()]))
.query(({input}) => input[0] - input[1]),
multiply: trpc.procedure
.meta({
description:
'Multiply two numbers together. Useful if you want to count the number of tiles on your bathroom wall and are short on time.',
})
.input(
z.object({
left: z.number().describe('The first number'),
right: z.number().describe('The second number'),
}),
)
.query(({input}) => input.left * input.right),
.input(z.tuple([z.number(), z.number()]))
.query(({input}) => input[0] * input[1]),
divide: trpc.procedure
.meta({
version: '1.0.0',
Expand All @@ -112,25 +232,23 @@ const router = trpc.router({
examples: 'divide --left 8 --right 4',
})
.input(
z.object({
left: z.number().describe('The numerator of the division operation.'),
right: z
z.tuple([
z.number().describe('numerator'),
z
.number()
.refine(n => n !== 0)
.describe(
'The denominator of the division operation. Note: must not be zero.',
),
}),
.describe('denominator'),
]),
)
.mutation(({input}) => input.left / input.right),
.mutation(({input}) => input[0] / input[1]),
})

void trpcCli({router}).run()
```
<!-- codegen:end -->


Run `node path/to/yourfile.js --help` for formatted help text for the `sum` and `divide` commands.
Run `node path/to/cli --help` for formatted help text for the `sum` and `divide` commands.

<!-- codegen:start {preset: custom, require: tsx/cjs, source: ./readme-codegen.ts, export: command, command: './node_modules/.bin/tsx test/fixtures/calculator --help'} -->
`node path/to/calculator --help` output:
Expand Down Expand Up @@ -160,12 +278,10 @@ add
Add two numbers. Use this if you and your friend both have apples, and you want to know how many apples there are in total.
Usage:
add [flags...]
add [flags...] <parameter 1> <parameter 2>
Flags:
-h, --help Show help
--left <number> The first number
--right <number> The second number
-h, --help Show help
```
<!-- codegen:end -->
Expand All @@ -176,9 +292,18 @@ When passing a command along with its flags, the return value will be logged to
`node path/to/calculator add --left 2 --right 3` output:

```
5
```
add
Add two numbers. Use this if you and your friend both have apples, and you want to know how many apples there are in total.
Usage:
add [flags...] <parameter 1> <parameter 2>
Flags:
-h, --help Show help
Unexpected flags: left, right
```
<!-- codegen:end -->

Invalid inputs are helpfully displayed, along with help text for the associated command:
Expand All @@ -192,15 +317,12 @@ add
Add two numbers. Use this if you and your friend both have apples, and you want to know how many apples there are in total.
Usage:
add [flags...]
add [flags...] <parameter 1> <parameter 2>
Flags:
-h, --help Show help
--left <number> The first number
--right <number> The second number
-h, --help Show help
Validation error
- Expected number, received nan at "--right"
Unexpected flags: left, right
```
<!-- codegen:end -->

Expand Down Expand Up @@ -277,10 +399,10 @@ You could also override `process.exit` to avoid killing the process at all - see
Given a migrations router looking like this:

<!-- codegen:start {preset: custom, require: tsx/cjs, source: ./readme-codegen.ts, export: dump, file: test/fixtures/migrations.ts} -->
<!-- hash:ecb45f308d36ff6594396ebd189c9f31 -->
<!-- hash:8635f80f9309a63813b659a227270b73 -->
```ts
import * as trpcServer from '@trpc/server'
import {TrpcCliMeta, trpcCli} from 'trpc-cli'
import {trpcCli, type TrpcCliMeta} from 'trpc-cli'
import {z} from 'zod'

const trpc = trpcServer.initTRPC.meta<TrpcCliMeta>().create()
Expand Down Expand Up @@ -480,7 +602,9 @@ Flags:

## Programmatic usage

This library should probably _not_ be used programmatically - the functionality all comes from a trpc router, which has [many other ways to be invoked](https://trpc.io/docs/community/awesome-trpc). But if you really need to for some reason, you could override the `console.error` and `process.exit` calls:
This library should probably _not_ be used programmatically - the functionality all comes from a trpc router, which has [many other ways to be invoked](https://trpc.io/docs/community/awesome-trpc) (including the built-in `createCaller` helper bundled with `@trpc/server`).

The `.run()` function does return a value, but it's typed as `unknown` since the input is just `argv: string[]` . But if you really need to for some reason, you could override the `console.error` and `process.exit` calls:

```ts
import {trpcCli} from 'trpc-cli'
Expand All @@ -506,7 +630,7 @@ const runCli = async (argv: string[]) => {
}
```

Note that even if you do this, help text may get writted directly to stdout by `cleye`. If that's a problem, [raise an issue](https://github.com/mmkal/trpc-cli/issues) - it could be solved by exposing some `cleye` configuration to the `run` method.
>Note that even if you do this, help text is handled by [cleye](https://npmjs.com/package/cleye) which prints directly to stdout and exits the process. In a future version this will be solved by either exposing some `cleye` configuration to the `run` method, or controlling the help text rendering directly.
## Out of scope

Expand Down
3 changes: 2 additions & 1 deletion package.json
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Expand Up @@ -13,8 +13,9 @@
"packageManager": "pnpm@8.10.2",
"scripts": {
"prepare": "pnpm build",
"lint": "eslint .",
"lint": "eslint --max-warnings=0 .",
"build": "tsc -p tsconfig.lib.json",
"dev": "cd test/fixtures && tsx",
"test": "vitest run"
},
"repository": {
Expand Down
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