Node.js Yargs模块：命令行“ --help”未显示命令列表

Question

const yargs = require（'yargs'）;

console.log（yargs.argv）;

yargs.command（{

command:'add',
description: 'Helps add a note',
handler: function() {

    console.log("adding a new note")
}

} ）.parse（）;