Mutating props

Product2.vue

<template>
   <Product :product="product" @add-to-cart="addProductToCart(product)"></Product>
</template>

<script>
import Product from "./components/Product";

export default {
  name: "App",
  components: {
    Product
  },
  data() {
    return {
      product: {
        name: "Laptop",
        price: 1250,
        stock: 2
      }
    };
  },
  methods: {
    addProductToCart(product) {
      if (product.stock > 0) {
        product.stock--;
      }
    }
  }
};
</script>