totominc/command-parser

A modulable terminal command-parser trying to re-create a basic UNIX command-parser.

@totominc/command-parser

A modulable UNIX terminal command-parser, originally created for skid-inc incremental-game.

⚠️ this is an experimental library, getting new features and bug-fixes as I encounter them on skid-inc.

Usage

1. install using npm or yarn

npm i @totominc/command-parser --save
# or with Yarn
yarn add @totominc/command-parser

2. import in your code, see the API for exported functions

Basic usage using the parser function

// make sure to take a look at `public/index.ts` for more examples.

// the parser function is the default export of the module.
import parse, { Command } from '@totominc/command-parser';

// your array of commands which is needed everytime you want to parse or
// autocomplete a user-input.
const commands: Command[] = [{
  name: 'ssh',
  description: 'connect to another server which supports the SSH protocol',
  requireValue: true,
  // a command value which doesn't include the `@` character will be invalid.
  validation: (value) => value.indexOf('@') > -1,
  arguments: [
    {
      name: '--identity_file',
      alias: '-i',
      requireValue: true,
      // `--identity_file` argument value which doesn't include the `.ssh`
      // string will be invalid.
      validation: (value) => value.indexOf('.ssh') > -1,
    },
  ],
}];

// parse a user-input command and verify if it's a valid command with valid
// arguments.
const { command, parsedArgs, valid } = parse<Command>(
  'ssh -i ~/.ssh/rpi pi@home',
  commands,
);

console.log(command, parsedArgs, valid);

Dynamically autocomplete a user input

import { autocomplete, Command } from '@totominc/command-parser';

const commands: Command[] = [{
  name: 'ssh',
  description: 'connect to another server which supports the SSH protocol',
  requireValue: true,
  validation: (value) => value.indexOf('@') > -1,
  arguments: [
    {
      name: '--login_name',
      alias: '-l',
      requireValue: true,
      // it is possible to dynamically autocomplete the `--login_name` argument
      // value since it's possible to predicate the value with the
      // `possibilities` array (unlike the `validation` function).
      possibilities: ['root', 'admin', 'admin-bis'],
    },
  ],
}];

// autocomplete the `--login_name` argument value against the array of
// commands.
const suggestions = autocomplete('ssh -l ad', commands);

// `['admin', 'admin-bis']`
console.log(suggestions);

API

Functions

parser<C>(input, commands): { command, parsedArgs, valid }

Parse user-input, find the command and extract arguments. Test the validity of arguments and of the command value. Return the command found, parsed arguments and validity of the input.

This is the default export of the module, the parser function can be imported by doing this import awesomeParser from '@totominc/command-parser';.

Kind: global function

Parameters:

Param	Type	Description
input	string	user-input terminal command
commands	any[]	an array of commands with a type that extends Command

Returned:

Return	Type	Description
command	C or undefined	return the command found (or undefined if not found)
parsedArgs	ParsedArg[]	array of parsed arguments
valid	boolean	validity of the user-input

autocomplete<C>(input, commands): string[]

Autocomplete a user-input based on the array of Command passed. Automatically determinate if the value to autocomplete is an argument or a command name/value.

This function is used when you want to dynamically autocomplete a user-input, like in a shell. i.e.: cat ~/.zsh will show multiple files (.zshrc, .zsh_history).

Kind: global function

Parameters:

Param	Type	Description
input	string	user-input from the terminal
commands	any[]	an array of commands with a type that extends Command

findCommand<C>(value, commands): C | Command

Try to find the command from user-input command-name. You can use an extended command interface by passing it as a generic.

Kind: global function

Parameters:

Param	Type	Description
value	string	input containing the name of the command
commands	Command[]	an array of commands with a type that extends Command

Models

Command

interface Command {
  /** Name of the command */
  name: string;
  /** Description of the command (i.e.: can be displayed in the help command) */
  description: string;
  /** If the command require a value */
  requireValue: boolean;
  /** An array of command arguments */
  arguments?: CommandArgument[];
  /**
   * If the command require a value (not an argument value), have a list of
   * possibilities to display and to autocomplete. This is used by default
   * to check if the value is valid.
   */
  possibilities?: ((...args: any) => string[]) | string[];
  /**
   * If the command require a dynamic, non-predictable value, you can pass a
   * validator function.
   */
  validation?: (value: string) => boolean;
}

CommandArgument

interface CommandArgument {
  /** Name of the argument */
  name: string;
  /** Alias of the argument instead of calling it by its name */
  alias?: string;
  /** If argument require a value, e.g.: `--identity_file ~/.ssh/key` */
  requireValue: boolean;
  /**
   * An array of possibilities if the argument require specific values, mostly
   * used by the autocomplete.
   *
   * If `valueValidation` function is not present, it will be used to determine
   * if the argument is valid.
   */
  possibilities?: ((...args: any) => string[]) | string[];
  /**
   * Function to validate the value of the argument, where context parameter
   * can help to determine what value to validate depending on the arguments
   * context.
   *
   * It can be used when you don't know the value in advance, like
   * validating a number or a specific string regex.
   */
  validation?: (value: string) => boolean;
}

ParsedArgument

interface ParsedArgument {
  /**
   * Nature/type of the argument:
   *
   * - `CMD_VALUE` is the value of a command.
   * - `ARG_NAME` is the name of an argument.
   * - `ARG_VALUE` is the value of an argument found by its `ARG_NAME`.
   */
  type: 'CMD_VALUE' | 'ARG_NAME' | 'ARG_VALUE';
  /**
   * Reflect the original `Command` or `CommandArgument`, can be undefined when
   * not able to recognize a command or argument being typed.
   */
  reflect?: Command | CommandArgument;
  /** Original value (from the input) of the argument */
  value: string;
  /** If the argument value is valid and matches */
  isValid: boolean;
}

Contributing

Contributions are welcome, make sure to add/edit tests when you are contributing.

License

See the MIT License file.