Example of converting a file to a dataURL in ES6

toDataUrl.js

const toDataURL = url => fetch(url)
    .then(response => response.blob())
    .then(blob => new Promise((resolve, reject) => {
      const reader = new FileReader()
      reader.onloadend = () => resolve(reader.result)
      reader.onerror = reject
      reader.readAsDataURL(blob)
    }))

@rohmanhm I have updated the gist. Totally missed that 😳