Is there a way to get the size of an image after resizing?

Does Sharp offer a simple way to get the size of an image after it has been resized?

Here’s roughly what I’m trying to accomplish:

const image = sharp(filepath);
// do other stuff with `image`
const thumbnail = image.clone().resize({height: THUMBNAIL_HEIGHT, fit: "inside"});

I’m using the inside fit option to automatically determine the correct width for the resized image. I thought Sharp#metadata() might be useful but then I read this line in the docs:

It does not include operations, such as resize, to be applied to the output image.

Does Sharp support what I am trying to accomplish?

[pjhartin]

Thanks @rawpixel-vincent, I adapted your example with an async variant.

const { info, data } = await sharp(fileOrBuffer)
    .withMetadata()
    .resize({
      width: 3000,
      height: 3000,
      withoutEnlargement: true,
      fit: 'inside'
    })
    .jpeg({
      quality: 80
    })
    .toBuffer({ resolveWithObject: true })

The size can then be accessed at info.size and the buffer is available at data.buffer.

Hope this helps someone else.

[lovell]

@Enchiridion The call to toBuffer() (or toFile, or pipe) triggers the pipeline and starts the calculations. If you need the output dimensions before the output is generated then you’ll have to calculate these in your own code.