Default values for optional parameters in options argument

Question

I want to pass an object as argument for the constructor of a class. Some keys of the options object are optional.

Is there a better / more idiomatic way of accomplishing the following in typescript? Thanks

class Car {
    color: number;
    numberOfWheels: number;

    constructor (options: {color: number, numberOfWheels?: number}) {
        options.numberOfWheels |= 4;

        this.color = options.color;
        this.numberOfWheels = options.numberOfWheels;
    }
}

Answer 1

Use if (options.numberOfWheels === void 0) { options.numberOfWheels = 4; } instead. (Otherwise 0 or NaN ... will be 4 as well)

Aside that what you do is actually pretty clever and it's the best you can do. Things like that won't work:

constructor (options: {color: number, numberOfWheels?: number} = {color: options.color})