angular4 upload image and pass to server and save into database(express and mongoose, mongodb) - mongodb

Question

Is there anyone knows how to upload an image within Angular 4 environment, then sending this data to the backend as express server, and using mongoose to store into mongodb? if anyone knows, please post the answer. Thank
File input
{{imgfile.errors | json}}
<div class="alert alert-danger"
*ngIf="size >= 300000">
<strong>
Can't upload this image. check image size!!!
</strong>
</div>
Script
onFileChange(event) {
let reader = new FileReader();
if(event.target.files && event.target.files.length > 0) {
console.log(event.target.files)
let file = event.target.files[0];enter code here
this.size = file.size;
console.log(file.size);
if (file.size <= 300000) {
this.picSize = true;
}
reader.onload = () => {
this.new_food.image = reader.result;
};
reader.readAsDataURL(file);
}
}

Answer 1

onFileChange(event) {
let reader = new FileReader();
if(event.target.files && event.target.files.length > 0) {
console.log(event.target.files)
let file = event.target.files[0];enter code here
this.size = file.size;
console.log(file.size);
if (file.size <= 300000) {
this.picSize = true;
}
reader.onload = () => {
this.new_food.image = reader.result;
};
reader.readAsDataURL(file);
}
}