Why is array.push() not working correctly? - node.js

Question

I have a function which returns an array of dishes from a firestore database.
With console.log I check that the dish I want to push is correctly formatted, then push it.
Finally I console.log the array to check if everything is alright.
Here is what I got:
https://image.noelshack.com/fichiers/2019/05/5/1549048418-arraypush.png
switch (type) {
case "Plats": {
this.nourritureCollection.ref.get().then(data => {
let platArray : Plat[] = [];
data.docs.forEach(doc => {
this.plat.name = doc.data().nourritureJson.name;
this.plat.price = doc.data().nourritureJson.price;
this.plat.ingredients = doc.data().nourritureJson.ingredients;
this.plat.type = doc.data().nourritureJson.type;
this.plat.availableQuantity = doc.data().nourritureJson.availableQuantity;
this.plat.isAvailableOffMenu = doc.data().nourritureJson.isAvailableOffMenu;
this.plat.imgUrl = doc.data().nourritureJson.imgUrl;
this.plat.temp = doc.data().nourritureJson.temp;
console.log(this.plat)
platArray.push(this.plat);
});
console.log(platArray)
return platArray;
});
break;
}...
plat is instantiated within my service component, I couldn't declare a new Plat() inside my function.
The expected result is that dishes should be different in my array of dishes.

Answer 1

You are updating this.plat in every iteration. So it will have n number of references in the array pointing to the same object, therefore, the values for all the array elements will be last updated value of this.plat
What you need is to create new Plat object for every iteration.
data.docs.forEach(doc => {
let plat: Plat = new Plat();
plat.name = doc.data().nourritureJson.name;
plat.price = doc.data().nourritureJson.price;
plat.ingredients = doc.data().nourritureJson.ingredients;
plat.type = doc.data().nourritureJson.type;
plat.availableQuantity = doc.data().nourritureJson.availableQuantity;
plat.isAvailableOffMenu = doc.data().nourritureJson.isAvailableOffMenu;
plat.imgUrl = doc.data().nourritureJson.imgUrl;
plat.temp = doc.data().nourritureJson.temp;
console.log(plat)
platArray.push(plat);
});
As pointed out in the comment, you can only use new Plat() if Plat is a class, if it is an interface, just let plat:Plat; would do.