[Client-Side]: from file URL to Base64

getBase64.js

const getBase64 = fileURL =>
  new Promise(async resolve => {
    const response = await fetch(fileURL);
    const blob = await response.blob();

    const reader = new FileReader();
    reader.readAsDataURL(blob);
    reader.onloadend = () => {
      const base64data = reader.result;
      resolve(base64data);
    };
  });

// Usage
const getFileBase64 = async () => {
  const result = await getBase64('http://localhost:3000/images/sample.jpeg');
  console.log(result);
};