spinner.js

exports.default = class Spinner {

   constructor(key, consoleFunc, consoleType, logMessage, cliSpinner, buildLogStringFunc) {

      this.key = key
      this.consoleFunc = consoleFunc
      this.consoleType = Object.assign({}, consoleType)
      this.logMessage = new String(logMessage)
      this.cliSpinner = cliSpinner
      this.buildLogString = buildLogStringFunc
      this.nextFrameIndex = 0
      this.stopRendering = false

      this.getKey = this.getKey.bind(this)
      this.render = this.render.bind(this)
      this.start = this.start.bind(this)
      this.stop = this.stop.bind(this)
      this.update = this.update.bind(this)

   }

   getKey() { return this.key }

   render(firstTime) {

      if (this.stopRendering) {

         return

      }

      // advance frame
      this.consoleType.bullet.chars = this.cliSpinner.frames[this.nextFrameIndex++]

      // build render string
      let logString = this.buildLogString(this.consoleType, this.logMessage, !firstTime)

      // render
      this.consoleFunc(logString)

      if (this.nextFrameIndex === this.cliSpinner.frames.length) {

         // loop the frames (i.e. reset)
         this.nextFrameIndex = 0

      }

      setTimeout(this.render, this.cliSpinner.interval)

   }

   start() { this.render(true) }

   stop() { this.stopRendering = true }

   update (message) { this.logMessage = new String(message) }

}

//
//
// private helper methods
//
//

const escapeColor = function(color) { return `\x1b[${color}m` }

const prepend = function(prependObj, logString, colors) {

   const { color = 39, chars = '', leftPadding = 0, rightPadding = 1 } = prependObj
   return `${escapeColor(color)}${' '.repeat(leftPadding)}${chars}${' '.repeat(rightPadding)}${logString}`

}