Resize image before saving with Node.js

Question

I have an upload function like this :

app.post("/upload", function (req, res) {
  let base64 = req.body.image.replace(/^data:image\/png;base64,/, "");
  binaryData = Buffer.from(base64, "base64").toString("binary");

  fs.writeFile(
    "./pictures/" + Date.now() + ".png",
    binaryData,
    "binary",
    function (err) {
      if (err) {
        console.log(err);
      }
    }
  );

  fs.writeFile(
    "./thumbnails/" + Date.now() + ".png",
    binaryData,
    "binary",
    function (err) {
      if (err) {
        console.log(err);
      }
    }
  );

The first part saves image into "pictures" folder. That works ok, nothing to do here.

The second parts saves the same image into "thumbnails" folder. What I need to do is to resize the image before its saved, to have only resized images in that folder.

Answer 1

You can try with Sharp library: https://sharp.pixelplumbing.com/api-resize

app.post("/upload", function (req, res) {
let base64 = req.body.image.replace(/^data:image\/png;base64,/, "");
binaryData = Buffer.from(base64, "base64").toString("binary");

fs.writeFile(
    "./pictures/" + Date.now() + ".png",
    binaryData,
    "binary",
    function (err) {
        if (err) {
            console.log(err);
        }
    }
);

sharp(binaryData)
    .resize({ width: 100 })
    .toBuffer()
    .then(data => {
        // 100 pixels wide, auto-scaled height
        fs.writeFile(
            "./thumbnails/" + Date.now() + ".png",
            data,
            "binary",
            function (err) {
                if (err) {
                    console.log(err);
                }
            }
        )
    })
})