Getting the Nightmare.JS (v 2.9.1) screenshot buffer

Question

I'm trying to take a screenshot of a webpage with the code below. With some slight modification, I can save the screenshot as a PNG. However, nightmare.JS docs indicate the .screenshot() method will return "a Buffer of the image data." if a "path" option is not provided.

How can I get access to the buffer once the screenshot has completed execution?

const getScreenshot = (url) => {
    nightmare
    .goto(url)
    .wait()
    .evaluate(() => {
        const body = document.querySelector('body');

        return {
            height: body.scrollHeight,
            width: body.scrollWidth
        };
    })
    .then(function(dimensions) {
        return nightmare
        .viewport(dimensions.width, dimensions.height)
        .wait(1000)
        // .screenshot(require('path').join(__dirname, 'screenshot.png'))
        .screenshot()
    })
    .then(function(e) {
        console.log('nightmare', nightmare)
        nightmare.end()
            .then(function(result) {
            console.log('completed screenshot', result)
            console.log('done');
        })
    });
}

Answer 1

You are almost there: in your final .then(), e should be the completed buffer for the PNG. To verify, you can change the .then() function slightly:

    function(e) {
      //this should print "e is a buffer: true"
      console.log(`e is a buffer: ${Buffer.isBuffer(e)}`);

      return nightmare.end()
        .then(function(result) {
          console.log('completed screenshot', result)
          console.log('done');
        });
   }