TypeScript TypeScript Core Types Types in function arguments and return value. Number
Example
When you create a function in TypeScript you can specify the data type of the function's arguments and the data type for the return value
Example:
function sum(x: number, y: number): number {
return x + y;
}
Here the syntax x: number, y: number means that the function can accept two argumentsx and y and they can only be numbers and (...): number { means that the return value can only be a number
Usage:
sum(84 + 76) // will be return 160
Note:
You can not do so
function sum(x: string, y: string): number {
return x + y;
}
or
function sum(x: number, y: number): string {
return x + y;
}
it will receive the following errors:
error TS2322: Type 'string' is not assignable to type 'number' and error TS2322: Type 'number' is not assignable to type 'string' respectively
