What is oclif?
oclif is a framework for building command-line interfaces (CLIs) in Node.js. It provides a robust set of tools and conventions for creating and managing CLI applications, including support for plugins, argument parsing, and command scaffolding.
What are oclif's main functionalities?
Command Creation
This feature allows you to create new commands easily. The example demonstrates a simple 'Hello, world!' command.
const { Command } = require('@oclif/core');
class HelloWorldCommand extends Command {
async run() {
this.log('Hello, world!');
}
}
HelloWorldCommand.run();
Argument Parsing
This feature provides built-in support for parsing command-line arguments and flags. The example shows a command that greets a user by name.
const { Command, flags } = require('@oclif/core');
class GreetCommand extends Command {
static flags = {
name: flags.string({ char: 'n', description: 'name to print' })
};
async run() {
const { flags } = this.parse(GreetCommand);
this.log(`Hello, ${flags.name || 'world'}!`);
}
}
GreetCommand.run();
Plugins
This feature allows you to extend your CLI with plugins. The example demonstrates loading plugins within a command.
const { Command } = require('@oclif/core');
const { Plugins } = require('@oclif/plugin-plugins');
class MyCommand extends Command {
async run() {
const plugins = new Plugins(this.config);
await plugins.load();
this.log('Plugins loaded');
}
}
MyCommand.run();
Other packages similar to oclif
commander
Commander is a popular library for building command-line interfaces in Node.js. It provides a simple and flexible API for defining commands, options, and arguments. Compared to oclif, Commander is more lightweight and less opinionated, making it a good choice for simpler CLI applications.
yargs
Yargs is another widely-used library for building CLI applications in Node.js. It offers powerful argument parsing capabilities and a rich set of features for handling complex command-line interfaces. Yargs is more feature-rich than Commander but still less structured than oclif, which provides a more comprehensive framework for CLI development.
vorpal
Vorpal is a framework for building interactive command-line applications in Node.js. It supports features like command history, tab completion, and interactive prompts. Vorpal is more focused on creating interactive CLIs, whereas oclif is designed for building both simple and complex command-line tools.
oclif: Node.JS Open CLI Framework
π Description
This is a framework for building CLIs in Node.js. This framework was built out of the Heroku CLI but generalized to build any custom CLI. It's designed both for simple CLIs that can be just a single file with a few flag options, or for very complex CLIs that have subcommands (like git or heroku).
See the docs for more information.
π Getting Started Tutorial
The Getting Started tutorial is a step-by-step guide to introduce you to oclif. If you have not developed anything in a command line before, this tutorial is a great place to get started.
β¨ Features
- Flag/Argument parsing - No CLI framework would be complete without a flag parser. We've built a custom one from years of experimentation that we feel consistently handles user input flexible enough for the user to be able to easily use the CLI in ways they expect, but without comprisiming strictness guarantees to the developer.
- Super Speed - The overhead for running an oclif CLI command is almost nothing. Also, only the command to be executed will be required with node. So large CLIs with many commands will load just as fast as a small one with a single command.
- CLI Generator - Run a single command to scaffold out a fully functional CLI and get started quickly. See Usage below.
- Testing Helpers - We've put a lot of work into making commands easily testable and easy to mock out stdout/stderr. The generator will automatically create scaffolded tests.
- Auto-documentation - By default you can pass
--help
to the CLI to get help such as flag options and argument information. This information is also automatically placed in the README whenever the npm package of the CLI is published. See the multi-command CLI example - Plugins - Using plugins, users of the CLI can extend it with new functionality, a CLI can be split into modular components, and functionality can be shared amongst multiple CLIs. See Building your own plugin below.
- Hooks - Use lifecycle hooks to run functionality any time a CLI starts, or on custom triggers. Use this whenever custom functionality needs to be shared between various components of the CLI.
- TypeScript (or not) - Everything in the core of oclif is written in TypeScript and the generator can build fully configured TypeScript CLIs or just plain JavaScript CLIs. By virtue of static properties in TypeScript the syntax is a bit cleaner in TypeScriptβbut everything will work no matter which language you choose. If you use plugins support, the CLI will automatically use
ts-node
to run the plugins making it easy and fast to use TypeScript with minimal-to-no boilerplate needed for any oclif CLI. - Coming soon: man pages - In addition to in-CLI help through
--help
and the README markdown help generation, the CLI can also automatically create man pages for all of its commands. - Coming soon: Autocomplete - Automatically include autocomplete for your CLI. This includes not just command names and flag names, but flag values as well. For example, it's easy to configure the Heroku CLI to have completions for Heroku app names:
$ heroku info --app=<tab><tab> # will complete with all the Heroku apps a user has in their account
π Requirements
Only Node 8+ is supported. Node 6 will reach end-of-life April 2019. At that point we will continue to support the current LTS version of node. You can add the node package to your CLI to ensure users are on Node 8.
π CLI Types
With oclif you can create 2 different CLI types, single and multi.
Single CLIs are like ls
or cat
. They can accept arguments and flags. Single CLIs can optionally be just be a single file.
Multi CLIs are like git
or heroku
. They have subcommands that are themselves single CLIs. In the package.json
there is a field oclif.commands
that points to a directory. This directory contains all the subcommands for the CLI. For example, if you had a CLI called mycli
with the commands mycli create
and mycli destroy
, you would have a project like the following:
package.json
src/
βββ commands/
Β Β βββ create.ts
Β Β βββ destroy.ts
Multi-command CLIs may also include plugins.
See below for information on nesting commands within topics.
π Usage
Creating a single-command CLI:
$ npx oclif single mynewcli
? npm package name (mynewcli): mynewcli
$ cd mynewcli
$ ./bin/run
hello world from ./src/index.js!
Creating a multi-command CLI:
$ npx oclif multi mynewcli
? npm package name (mynewcli): mynewcli
$ cd mynewcli
$ ./bin/run --version
mynewcli/0.0.0 darwin-x64 node-v9.5.0
$ ./bin/run --help
USAGE
$ mynewcli [COMMAND]
COMMANDS
hello
help display help for mynewcli
$ ./bin/run hello
hello world from ./src/hello.js!
π Examples
Commands
command NAME
add a command to an existing CLI or plugin
USAGE
$ oclif command NAME
ARGUMENTS
NAME name of command
OPTIONS
--defaults use defaults for every setting
--force overwrite existing files
See code: src/commands/command.ts
help [COMMAND]
display help for oclif
USAGE
$ oclif help [COMMAND]
ARGUMENTS
COMMAND command to show help for
OPTIONS
--all see all commands in CLI
See code: @oclif/plugin-help
multi [PATH]
generate a new multi-command CLI
USAGE
$ oclif multi [PATH]
ARGUMENTS
PATH path to project, defaults to current directory
OPTIONS
--defaults use defaults for every setting
--force overwrite existing files
--options=options (yarn|typescript|tslint|semantic-release|mocha)
See code: src/commands/multi.ts
plugin [PATH]
create a new CLI plugin
USAGE
$ oclif plugin [PATH]
ARGUMENTS
PATH path to project, defaults to current directory
OPTIONS
--defaults use defaults for every setting
--force overwrite existing files
--options=options (yarn|typescript|tslint|semantic-release|mocha)
See code: src/commands/plugin.ts
single [PATH]
generate a new single-command CLI
USAGE
$ oclif single [PATH]
ARGUMENTS
PATH path to project, defaults to current directory
OPTIONS
--defaults use defaults for every setting
--force overwrite existing files
--options=options (yarn|typescript|tslint|semantic-release|mocha)
See code: src/commands/single.ts
π Related Repositories
π¦ Learn More
π£ Feedback
If you have any suggestions or just want to let us know what you think of oclif, send us a message at heroku-cli@salesforce.com