TypeScript: RGB Class Example

color.ts

export type Difference = (a: number, b: number) => number

export default class Color {
    protected red: number
    protected green: number
    protected blue: number
    protected opacity?: number

    static HEX_MIN = 0
    static HEX_MAX = 255

    constructor(red: number, green: number, blue: number, opacity?: number) {
        this.red = red
        this.green = green
        this.blue = blue
        this.opacity = opacity || 1.0
    }

    public toString(): string{
        return `rgba(${this.red}, ${this.green}, ${this.blue}, ${this.opacity})`
    }

    public toHex(): string {
        return '#' + [
            this.red,
            this.green,
            this.blue
        ]
        .map((c: number): string => `0${c.toString(16)}`.slice(-2).toUpperCase())
        .join('')
    }

    public invert(): Color {
        return new Color(
            Color.HEX_MAX - this.red,
            Color.HEX_MAX - this.green,
            Color.HEX_MAX - this.blue
        )
    }

    public difference(c: Color, diff?: Difference): Color {
        if (!diff) {
            diff = (a, b) => Math.abs(a - b)
        }

        return new Color(
            diff(this.red, c.red),
            diff(this.green, c.green),
            diff(this.blue, c.blue)
        )
    }
}