upload file in angular 2 with nodejs - node.js

Question

I am new in angular 2 and node js.
I need to upload file in folder using anjular2 and also want to store that file name in mongodb database, at server side. For that I tried this but its not working.Using code is that:
app.component.ts:
attachment: any;
hasBaseDropZoneOver: boolean = false;
options: Object = {
url: 'http://localhost:3000/upload'
};
sizeLimit = 2000000;
handleUpload(data): void {
if (data && data.response) {
this.attachment = data;
}
}
fileOverBase(e:any):void {
this.hasBaseDropZoneOver = e;
}
beforeUpload(uploadingFile): void {
console.log(uploadingFile.size + ' -- '+this.sizeLimit);
if (uploadingFile.size > this.sizeLimit) {
uploadingFile.setAbort();
alert('File is too large');
}
}
this is app.html file:-
<input type="file" ngFileSelect [options]="options" (onUpload)="handleUpload($event)" (beforeUpload)="beforeUpload($event)">
app.module.ts
import { Ng2UploaderModule } from 'ng2-uploader';
Server Side Code:
const upload = multer({
dest: 'uploads/',
storage: multer.diskStorage({
filename: (req, file, cb) => {
let ext = path.extname(file.originalname);
cb(null, `${Math.random().toString(36).substring(7)}${ext}`);
}
})
});
app.post('/upload', upload.any(), (req, res) => {
res.json(req.files.map(file => {
let ext = path.extname(file.originalname);
return {
originalName: file.originalname,
filename: file.filename
}
}));
});
It is showing me below error:
XMLHttpRequest cannot load http://localhost:3000/upload. Response to preflight request doesn't pass access