angular-cli/packages/@angular/cli/commands/help.ts

import chalk from 'chalk';
import * as fs from 'fs';
import * as path from 'path';

const { cyan } = chalk;
const Command = require('../ember-cli/lib/models/command');
const stringUtils = require('ember-cli-string-utils');
const lookupCommand = require('../ember-cli/lib/cli/lookup-command');

const HelpCommand = Command.extend({
  name: 'help',
  description: 'Shows help for the CLI.',
  works: 'everywhere',

  availableOptions: [],

  anonymousOptions: [],

  run: function (_commandOptions: any, _rawArgs: any) {
    let commandFiles = fs.readdirSync(__dirname)
      // Remove files that are not JavaScript or Typescript
      .filter(file => file.match(/\.(j|t)s$/) && !file.match(/\.d.ts$/))
      .map(file => path.parse(file).name)
      .map(file => file.toLowerCase());

    let commandMap = commandFiles.reduce((acc: any, curr: string) => {
      let classifiedName = stringUtils.classify(curr);
      let defaultImport = require(`./${curr}`).default;

      acc[classifiedName] = defaultImport;

      return acc;
    }, {});

    const commands = commandFiles
      .map(commandFile => {
        const Command = lookupCommand(commandMap, commandFile);

        const cmd = new Command({
          ui: this.ui,
          project: this.project,
          commands: this.commands,
          tasks: this.tasks
        });

        return cmd;
      })
      .filter(cmd => !cmd.hidden && !cmd.unknown)
      .map(cmd => ({ name: cmd.name, description: cmd.description }));
    this.ui.writeLine(`Available Commands:`);
    commands.forEach(cmd => {
      this.ui.writeLine(`  ${cyan(cmd.name)} ${cmd.description}`);
    });
    this.ui.writeLine(`\nFor more detailed help run "ng [command name] --help"`);
  }
});

HelpCommand.overrideCore = true;
export default HelpCommand;