How to get Delta Time in Phaser 3

Recently I had a project that required me to use Unity and I liked how the deltaTime was built in. I’ve been using elapsed time in a lot of code from Flash to Phaser, but it occurred to me that developers that were moving between Unity and Phaser might be looking for a way to get the Delta or elapsed time between two different events. In this simple example, I use the “pointerdown” event to show time between clicks.

class SceneMain extends Phaser.Scene {
    constructor() {
        super('SceneMain');
    }
    preload() {}
    create() {
        //record the start time
        this.start = this.getTime();

        //add a listener for when the screen is clicked
        this.input.on('pointerdown',this.showDelta.bind(this));
    }
    getTime() {
        //make a new date object
        let d = new Date();

        //return the number of milliseconds since 1 January 1970 00:00:00.
        return d.getTime();
    }
    showDelta() {
        //subtract the start time from the time now
        // 
        let elapsed = this.getTime()-this.start;

        //log the result
        console.log("delta time=" + elapsed);

        //reset the start time
        this.start = this.getTime();
    }
    update() {}
}