I have an interface with the following:
interface orderItem {
symbol: string,
side: string,
price: number
quantity: number
}
I want to create an array "orders" consisting of "orderItems" in my constructor.
However, orders : [orderItem] doesn't seem to be doing the trick. Does anyone know how I can proceed?
Here is what I am trying to do in my constructor:
this.state = {
orders: orderItem []
}
Since you're doing an object literal, the colon is used to divide the key from the value (ie, it has its normal javascript meaning, not its typescript meaning). As a result, trying to set the type the way you're doing is causing an error.
There are a few ways you could do what you want. You could set the type using the as keyword:
this.state = {
orders: undefined as orderItem[]
};
or with an empty array:
this.state = {
orders: [] as orderItem[]
};
Or you could create something ahead of time, and then insert that into the object:
let myOrders: orderItem[] = [];
this.state = {
orders: myOrders
};
Or you could have a separate interface for the state and use that:
interface myState {
orders: orderItem[]
}
class myClass {
private state: myState;
constructor () {
this.state = {
orders: undefined
}
}
}
What you want is this:
this.orders = new Array<orderItem>();
You need to declare it like this:
interface CartState extends Object { orders: OrderItem[] }
class Cart {
private state: CartState;
constructor(orders: OrderItem[]) {
this.state = { orders };
}
}
Typescript documentation for declaring arrays.
