How do I get the ElementHandle's class name when using Puppeteer?

Question

I'm trying to get an ElementHandle's class name using Puppeteer... is it possible? Am I using the wrong approach? In this jsBin is part of my code, so you can understand what I am trying to achieve.

CriticalCssPlugin.prototype.load = function( page, src ) {
  return page.goto( src, { waitUntil: 'networkidle2' } )
    .then( () => {
      return page
        .$$( '*' )
        .then( elements => {
          return Promise.all( elements.map( element => {
            return element.boundingBox()
          } ) )
            .then( positions => {
              let visible = positions.filter( ( rect, index ) => {
                if ( !rect ) {
                  return rect
                }

                rect.element = elements[ index ]

                return this.isAnyPartOfElementInViewport( rect, page.viewport() )
              } )

              this.getClasses( visible )
            } )
        } )
    } )
}

CriticalCssPlugin.prototype.getClasses = function( visibles ) {
  Promise.all( visibles.map( visible => {
    return visible.element.getProperty( '' )
  } ) )
    .then( classes => {
      console.log(classes);
    } )
}

CriticalCssPlugin.prototype.isAnyPartOfElementInViewport = function( rect, viewport ) {
  const windowHeight = viewport.height
  const windowWidth = viewport.width
  const vertInView = ( rect.y <= windowHeight ) && ( ( rect.y + rect.height ) >= 0 )
  const horInView = ( rect.x <= windowWidth ) && ( ( rect.x + rect.width ) >= 0 )

  return ( vertInView && horInView )
}

https://jsbin.com/kuzejoluji/edit?js,output

Thank you :D

Answer 1

Going to drop this here since this page is currently first result searching for "elementhandle class name"

From the docs, you should just be able to the following

const el = await page.$('.myElement')
const className = await el.getProperty('className')

// alternatively,
// page.$('.myElement')
//    .then(el => el.getProperty('className'))
//    .then(className => ... )

Answer 2

jimmyjoy's answer is right but this may help others use the elementHandle

  page.$(el) // This grabs the element (returns a elementHandle)
    .then((el) => el.getProperty("className")) // Returns a jsHandle of that property
    .then((cn) => cn.jsonValue()) // This converts the className jsHandle to a space delimitedstring       
    .then((classNameString) => classNameString.split(" ") // Splits into array
    .then((x) => console.log(x)

Which would log an array of classes

Note: when i tried to do a .split on the end of jsonValue() it didn't work as i believe the promise isn't resolved at that point so cn.jsonValue().split(" ") wont work

---

References

List of properties on elements

Puppeteer docs for ElementHandle

Answer 3

I found a solution that helps in parts, but it was good enough to me. I've got the class name acessing ElementHandle._remoteObject.description. Hope this helps someone.

Answer 4

you can get the element variable and use evaluate function like that:

const element = await page.$(".some-class"); // for ids you can write "#some-id"
const className = await page.evaluate(el => el.className, element);
console.log('className', className) // here you can get the class name