Promise based file to base64 conversion

file_to_base64.js

/**
 * Converts file to base64
 *
 * @param {File} file
 * @return {Promise<String>}
 */
export default file => {
    return new Promise(resolve => {
        const reader = new FileReader();
        reader.readAsDataURL(file);
        reader.onload = () => resolve(reader.result);
    })
}

Approximately usage:

import file_to_base64 from "@/helpers/file_to_base64";

/**
 * Event listener for input
 *
 * @param {File} file
 */
const onInputChange = async file => {
    const content = await file_to_base64(file);

    // ...
}

A very helpful helper for handling files. Thank you, what we needed.

Bravo! A very Useful hint!