comline

comline

bun i comline

comline makes it easy to turn a typescript function into a command line tool.

usage

let's say we have the following function defined in greet.ts:

/**
 * @param {string} name
 * @param {number} age
 * @returns {string}
 */
function greet(name: string, age: number): string {
  return `Hello, ${name}!`
}

create a greet.x.ts file with the following contents:

import { greet } from "./greet"

import { cli, parseNumberArg, parseStringArg } from "comline"
import { z } from "zod"

const greetCli = cli({
  cliName: "greet",
  discoverConfigPath: (positionalArgs) => path.join(process.cwd(), `.greet-config.json`),
  optionsSchema: z.object({
    name: z.string(),
    age: z.number(),
  }),
  options: {
    name: {
      description: `name`,
      example: `--name=hello`,
      flag: `n`,
      parse: parseStringArg,
      required: true,
    },
    age: {
      description: `age`,
      example: `--age=1`,
      flag: `a`,
      parse: parseNumberArg,
      required: true,
    },
  },
})

const { suppliedOptions: { name, age } } = greetCli(process.argv)
const output = greet(name, age) 
process.stdout.write(output)

then, run the file greet.x.ts with the following command:

bun greet.x.ts --name=jeremybanka --age=1

this will print Hello, jeremybanka!

features

• switches (--age)
  • "" will be provided to the parse function for age in this case
• switches with values (--age=1)
  • "1" will be provided to the parse function for age in this case
• multiple instances of the same switch (--age=1 --age=2)
  • "1,2" will be provided to the parse function for age in this case
• flags (-a)
  • "" will be provided to the parse function for age in this case
• multiple instances of the same flag (-aa)
  • "," will be provided to the parse function for age in this case
• flags with values (-a=1)
  • "1" will be provided to the parse function for age in this case
• combined flags (-na)
  • "" will be provided to the parse function for name in this case
  • "" will be provided to the parse function for age in this case
• positional arguments (my-cli -- positional)
  • validated as a "route" into the tree of positional arguments

  import type { Tree, TreePath } from "comline"
  import { optional, required } from "comline"
  
  const myTree = required({
      hello: optional({
    	  world: null,
    	  $name: optional({
    		  good: required({
    			  morning: null,
    		  }),
    	  }),
  	}),
  }) satisfies Tree
  
  const validPaths: TreePath<typeof myTree>[] = [
    [`hello`],
    [`hello`, `world`],
    [`hello`, `jeremybanka`],
    [`hello`, `jeremybanka`, `good`, `morning`],
  ]
  

limitations

• comline supports positional arguments, but only following the -- convention.
• comline supports options with values, but only when using = to separate the option name from the value.
• flags are supported, but they must be single characters, either uppercase or lowercase.