convert-to-async

cta-route-with-promises-v2.js

  app.post('/process-upload', upload.single('image'), (req, res) => {
    // Define some helper methods that provide semantic names to the
    // actions in our route.
    const resizeAndConvert = buffer => (
      imConvertPromise({
        srcData: buffer,
        width: 32,
        height: 16,
        format: 'PNG'
      })
    );

    const readPixelsFromImage = buffer => (
      imageMagick.getConstPixels({
        srcData: buffer,
        x: 0,
        y: 0,
        columns: 32,
        rows: 16
      })
    );

    const saveToDisk = file => buffer => (
      // Save the file to disk, and then return the original buffer.
      // This is to preserve the data so it can be used further down the chain.
      writeFilePromise(getPathForNewFile(file), buffer)
        .then(() => buffer)
    );

    readFilePromise(req.file.path)
      .then(resizeAndConvert)
      .then(saveToDisk(req.file))
      .then(readPixelsFromImage)
      .then(pixels => {
        res.json({ done: true, pixels });
      }).catch(err => { throw err });