Javascript Promises with FileReader()

Question

I have the following HTML Code:

And Here\'s my JS Code:

var inputFiles = document.getE         


        

Answer 1

Promisified FileReader

/**
 * Promisified FileReader
 * More info https://developer.mozilla.org/en-US/docs/Web/API/FileReader
 * @param {*} file
 * @param {*} method: readAsArrayBuffer, readAsBinaryString, readAsDataURL, readAsText
 */
export const readFile = (file = {}, method = 'readAsText') => {
  const reader = new FileReader()
  return new Promise((resolve, reject) => {
    reader[method](file)
    reader.onload = () => {
      resolve(reader)
    }
    reader.onerror = (error) => reject(error)
  })
}

Usage

const file =  new File(["foo"], "foo.txt", {
  type: "text/plain",
});

// Text
const resp1 = await readFile(file)
console.log(resp1.result)

// DataURL
const resp2 = await readFile(file, 'readAsDataURL')
console.log(resp2.result)