Because async functions are promises, you can create a static function on your class which executes an async function which returns the instance of the class:

class Yql {
  constructor () {
    // Set up your class
  }
  
  static init () {
    return (async function () {
      let yql = new Yql()
      // Do async stuff
      await yql.build()
      // Return instance
      return yql
    }())
  }  

  async build () {
    // Do stuff with await if needed
  }
}

async function yql () {
  // Do this instead of "new Yql()"
  let yql = await Yql.init()
  // Do stuff with yql instance
}

yql()

Call with let yql = await Yql.init() from an async function.

Because async functions are promises, you can create a static function on your class which executes an async function which returns the instance of the class:

class Yql {
  constructor() {
    // Set up your class
  }
  
  static async init() {
    let yql = new Yql()
    // Do async stuff
    await yql.build()
    // Return instance
    return yql;
  }  

  async build() {
    // Do stuff with await if needed
  }
}

async function yql() {
  // Do this instead of "new Yql()"
  let yql = await Yql.init()
  // Do stuff with yql instance
}

yql()

Call with let yql = await Yql.init() from an async function.