nodejs convert image between buffer and string

Question

i want to convert png image from buffer to string, and then convert string to buffer.

fs.readFile('/Users/xxx/Desktop/1.png', (err, data) => {
    if (err) throw err; // Fail if the file can't be read.
    data = Buffer.from(data)
    let str = data.toString()
    data = Buffer.from(str)
});

// server
router.register('/api/dump', (request, response) => { 
    fs.readFile('/Users/xxx/Desktop/1.png', (err, data) => {
        if (err) throw err; // Fail if the file can't be read. 
        response.writeHead(200, {'Content-Type': 'image/jpeg'}); 
        response.end(data); // Send the file data to the browser.
    });
}) 

// front
this.$get('/dump').then(result => {
    // i want to convert result to buffer
})

but the new buffer is not old buffer any more.

Answer 1

Buffer.toString() default encoding is utf8, and you can't convert from utf8 back to Buffer without breaking the image.

If you want to convert to string, and then back to buffer, you will need to use an encoding that allows this, for example base64.

fs.readFile('/Users/yihchu/Desktop/1.png', (err, data) => {
    if (err) throw err; // Fail if the file can't be read.
    var oldData = data;
    let str = data.toString('base64')
    data = Buffer.from(str, 'base64');
});