helper toBase64

helper.js

// helper.js
export async function toBase64(blob) {
  return new Promise((resolve, reject) => {
    const reader = new FileReader()
    let fullStr = ''

    const getPositionSymbol = symbol => {
      return fullStr.search(symbol) + 1
    }

    reader.readAsDataURL(blob)

    reader.onload = () => {
      fullStr = reader.result
      const content = fullStr.substring(getPositionSymbol(','))
      const type = fullStr.substring(getPositionSymbol(':'), getPositionSymbol(';') - 1)

      resolve({ content, type })
    }

    reader.onerror = error => reject(error)
  })
}

// index.js
import { toBase64 } from './helper'

const { content, type } await toBase64(file) // the file comes from an input type file

const file = {
    name: file.name,
    content,
    type
}