Hands-On Functional Programming with TypeScript

Function overloading

Function, or method, overloading is the ability to create multiple methods with the same name and a different number of parameters or types. In TypeScript, we can overload a function by specifying all function signatures (known as overload signatures) of a function, followed by a signature (known as the implementation signature). Let's look at an example:

function test(name: string): string; // overloaded signaturefunction test(age: number): string; // overloaded signaturefunction test(single: boolean): string; // overloaded signaturefunction test(value: (string|number|boolean)): string { // implementation signature    switch (typeof value) {        case "string":            return 'My name is ${value}.';        case "number": return 'I'm ${value} ...