Sharp: Saving Base64 format

[sonnyk22]

Excellent library!!!

Two quick questions.

1) Is there a way to savea Base64 image in a string variable as a resized image?
2) are there available option(s) to read an image file (.jpg) and overridingit by saving a resized version of it in the same directory path?

Thank you!

[papandreou]

1. You can just use Buffer#toString and pass base64:

const resizedImageBuf = await require('sharp')(pathToMyImage)
  .resize(32, 32)
  .toBuffer();

console.log(`data:image/png;base64,${resizedImageBuf.toString('base64')}`);
// data:image/png;base64,iVBORw0KGgoAAAANS...

(you need to match the Content-Type with the type of the resulting image, of course)

[lovell]

1. When using the filesystem, the output file will be opened and written to before the input file has finished reading and closed, so these cannot be the same.

[sonnyk22]

Thank you to you both for helping me on this!

[sonnyk22]

One more quick question in relation to the question number 1 above.

Let assume this time I have a Base64 image in a string variable and have already trimmed off the Content-Type (data:image/png). How can I save the content in this variable to a file with the .resize(32, 32) function mentioned above?

Thank you!

[papandreou]

@sonnyk22, that sounds like a job for fs.writeFile. Something like:

const writeFileAsync = require('util').promisify(require('fs').writeFile);
const resizedImageBuf = await require('sharp')(pathToMyImage)
  .resize(32, 32)
  .toBuffer();

await writeFileAsync('outputFile.txt', resizedImageBuf.toString('base64'), 'utf-8');

[sonnyk22]

fantastic! Another great solution to one of my issue. Thank you again!