[typescript] How can I define an array of objects?

What you really want may simply be an enumeration

If you're looking for something that behaves like an enumeration (because I see you are defining an object and attaching a sequential ID 0, 1, 2 and contains a name field that you don't want to misspell (e.g. name vs naaame), you're better off defining an enumeration because the sequential ID is taken care of automatically, and provides type verification for you out of the box.

enum TestStatus {
    Available,     // 0
    Ready,         // 1
    Started,       // 2
}

class Test {
    status: TestStatus
}

var test = new Test();
test.status = TestStatus.Available; // type and spelling is checked for you,
                                    // and the sequence ID is automatic

The values above will be automatically mapped, e.g. "0" for "Available", and you can access them using TestStatus.Available. And Typescript will enforce the type when you pass those around.

If you insist on defining a new type as an array of your custom type

You wanted an array of objects, (not exactly an object with keys "0", "1" and "2"), so let's define the type of the object, first, then a type of a containing array.

class TestStatus {
    id: number
    name: string

    constructor(id, name){
        this.id = id;
        this.name = name;
    }
}

type Statuses = Array<TestStatus>;

var statuses: Statuses = [
    new TestStatus(0, "Available"),
    new TestStatus(1, "Ready"),
    new TestStatus(2, "Started")
]