The TypeScript type annotation for array types is fairly straightforward: we put
 after the element type.
In this code,
names is an Array that can only contain
let names: string = ['Danny', 'Samantha'];
An alternative method is to use the
Array<T> syntax, where
T stands for the type.
let names: Array<string> = ['Danny', 'Samantha'];
In the code above, the type,
string. We won’t use
Array<T> syntax in this lesson, but it’s nice to be familiar with it.
As we may expect, we get a type error if we try to assign an array of
numbers to a
let names: string = [1,2,3]; // Type Error!
That was just like an assignment error with primitive types. TypeScript arrays, however, can also throw errors when elements of the wrong type are added:
let names: string = ['Damien']; names.push(666) // Type Error!
Let’s practice some array type annotations!
The code editor contains several array assignments. Add the appropriate type annotations to the array variables in the
// Arrays: section.