Save Nodejs receive a picture file format base64

base64 form of "data: image / png; base64 , iVBORw0KGgoAAAANSUhEUgAAABQAAAAUCAYAAACNiR0 ....";
after receiving the top of the content needs to be data: image / png; base64, this content was filtered off, filtered into: "iVBORw0KGgoAAAANSUhEUgAAABQAAAAUCAYAAACNiR0. .. "; then save it.

app.post('/upload', function(req, res){
    //接收前台POST过来的base64 var imgData = req.body.imgData; //过滤data:URL var base64Data = imgData.replace(/^data:image\/\w+;base64,/, ""); var dataBuffer = new Buffer(base64Data, 'base64'); fs.writeFile("image.png", dataBuffer, function(err) { if(err){ res.send(err); }else{ res.send("保存成功！"); } }); });