how do you declare an array of objects inside typescript?

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I would like to specify that function takes array of objects as parameter, but I don't have particular type defined for the object (sort of "anonymous type")

bagTotal = (products) => {
 // function does stuff
}

I understand I can do this:

bagTotal = (products: any[]) => {
 // function does stuff
}

but this is a bit more relaxed then what I want: to be strict with my typescript.

products is an array of same-looking objects like all objects have name, price, description.

how can I declare that?

I want to do something like

bagTotal = (products: [{name: string, price: number, description: string}]) => {
 // function does stuff
}

but that's not right. How can I declare this?

You're almost there, the placement of the brackets is just wrong:

{name: string, price: number, description: string}[]

The way you had it isn't entirely wrong, but it means something else: it means an array with exactly one item of this type.


I'd also recommend extracting it to an interface, it'd make the type reusable and the thing easier to read:

interface Product {
    name: string;
    price: number;
    description: string;
}

const products: Product[];

Exploiting TypeScript Arrays -- Visual Studio Magazine, In TypeScript, arrays are themselves a data type, just like number and declaring an array, you'll find that the resulting objects have exactly the  An array is a special type of data type which can store multiple values of different data types sequentially using a special syntax. TypeScript supports arrays, similar to JavaScript. There are two ways to declare an array: 1. Using square brackets. This method is similar to how you would declare arrays in JavaScript.

I think you must declare the class "Product" so you can declare a Product array like this:

products: Product[];

and pass it as a parameter like this:

bagTotal = (products: Product[]) => {
 // function does stuff
}

To have the class you can do a new .ts file with this code:

export class Product {
  name: String;
  price: Number;
  description: String;
}

I wish that helped!

Thank you.

TypeScript: object array declaration – Expert Code Blog, How can we define an array of objects in typescript? In TypeScript, arrays are themselves a data type. TypeScript provides a lot of ways for  To declare the array the following two syntaxes are valid, if you are looking for an option that avoids the use of an interface: contentOrderBy: { id: number, name: string, key: string }[]; or. contentOrderBy: Array<{ id: number, name: string, key: string }>; Then populate the array as in the OP's question.

If you are declaring an array of a specific object and want to specify type for variables in the objects, I would create a class for the object like this:

class Item(){
    name: string;
    description: string;
    etc: any

  constructor() {
    this.name;
    this.description;
    this.etc;
}}

Then you can specify the array as an array of item objects:

itemArray: Array<Item>;

TypeScript - Arrays, There are two ways to declare an array in typescript: 1. Using square brackets. Array Object. We can create an Array by using or initializing the Array Object. In this tutorial I am going to give you details about how you can declare object of a class in typescript. If you followed my earlier tutorials on typescript you will see that we have covered most of the basic learning essentials on typescript and and this tutorial series is mostly dedicated to the beginner developer.

TypeScript Arrays, This method is similar to how you would declare arrays in JavaScript. let fruits: Arrays can contain elements of any data type, numbers, strings, or even objects. I want to get the types of a specific element from an array of objects as const based on some given conditions. But I don't know how to do it. Example - const EXAMPLE = [ { type: 'tab', i

TypeScript Arrays, In the first, you use the type of the elements followed by [] to denote an array of that declare function create(o: object | null): void; create({ prop: 0 }); // OK  TypeScript Type Template. Let’s say you created an object literal in JavaScript as − var person = { firstname:"Tom", lastname:"Hanks" }; In case you want to add some value to an object, JavaScript allows you to make the necessary modification. Suppose we need to add a function to the person object later this is the way you can do this.

Basic Types · TypeScript, It returns the new length of the array. The push() method treats an array as a stack. Syntax. array.push(element1,element  For the initial object for which you want to create an array within another interface, you type "interface ISelectOptions { name1 : type; name2: type; } then within your BIG interface, when you get to the key you want to be an array of that type, keyZ: ISelectOptions[]; then when you create the JSON, myVar : BIG = {key1: val1, key2: val2, …, keyZ: [{name1 : valA, name2: valB}, {name1 : valC, name2: valD}] worked like a champ!

Comments
  • Why did you say it is not right ?
  • I would recommend using the Array<T> form if the item type is very large : Array<{name: string, price: number, description: string}>
  • I just added that I'd actually extract a type for it anyway ;)
  • @IngoBürk I slighted edited my question. please see. I can accept your answer if you answer that, thanks
  • @Red Baron products in your interface is still untyped, so what's the point? Also I'm rolling back that edit. Please don't change the question fundamentally after receiving answers. You asked a question, it has been answered. For a new question please open a new question.
  • ok I'll open a new question when it allows me too and accept this one. thanks