不知道为什么，最近看到的都是烟花特效，小球下落几乎看不到了，我在这里补一下。

//点击特效
class Circle {
    constructor({ origin, speed, color, angle, context }) {
        this.origin = origin
        this.position = { ...this.origin }
        this.color = color
        this.speed = speed
        this.angle = angle
        this.context = context
        this.renderCount = 0
    }

    draw() {
        this.context.fillStyle = this.color
        this.context.beginPath()
        this.context.arc(this.position.x, this.position.y, 2, 0, Math.PI * 2)
        this.context.fill()
    }

    move() {
        this.position.x = (Math.sin(this.angle) * this.speed) + this.position.x
        this.position.y = (Math.cos(this.angle) * this.speed) + this.position.y + (this.renderCount * 0.3)
        this.renderCount++
    }
}

class Boom {
    constructor({ origin, context, circleCount = 10, area }) {
        this.origin = origin
        this.context = context
        this.circleCount = circleCount
        this.area = area
        this.stop = false
        this.circles = []
    }

    randomArray(range) {
        const length = range.length
        const randomIndex = Math.floor(length * Math.random())
        return range[randomIndex]
    }

    randomColor() {
        const range = ['8', '9', 'A', 'B', 'C', 'D', 'E', 'F']
        return '#' + this.randomArray(range) + this.randomArray(range) + this.randomArray(range) + this.randomArray(range) + this.randomArray(range) + this.randomArray(range)
    }

    randomRange(start, end) {
        return (end - start) * Math.random() + start
    }

    init() {
        for (let i = 0; i < this.circleCount; i++) {
            const circle = new Circle({
                context: this.context,
                origin: this.origin,
                color: this.randomColor(),
                angle: this.randomRange(Math.PI - 1, Math.PI + 1),
                speed: this.randomRange(1, 6)
            })
            this.circles.push(circle)
        }
    }

    move() {
        this.circles.forEach((circle, index) => {
            if (circle.position.x > this.area.width || circle.position.y > this.area.height) {
                return this.circles.splice(index, 1)
            }
            circle.move()
        })
        if (this.circles.length == 0) {
            this.stop = true
        }
    }

    draw() {
        this.circles.forEach(circle => circle.draw())
    }
}

class CursorSpecialEffects {
    constructor() {
        this.computerCanvas = document.createElement('canvas')
        this.renderCanvas = document.createElement('canvas')

        this.computerContext = this.computerCanvas.getContext('2d')
        this.renderContext = this.renderCanvas.getContext('2d')

        this.globalWidth = window.innerWidth
        this.globalHeight = window.innerHeight

        this.booms = []
        this.running = false
    }

    handleMouseDown(e) {
        const boom = new Boom({
            origin: { x: e.clientX, y: e.clientY },
            context: this.computerContext,
            area: {
                width: this.globalWidth,
                height: this.globalHeight
            }
        })
        boom.init()
        this.booms.push(boom)
        this.running || this.run()
    }

    handlePageHide() {
        this.booms = []
        this.running = false
    }

    init() {
        const style = this.renderCanvas.style
        style.position = 'fixed'
        style.top = style.left = 0
        style.zIndex = '999999999999999999999999999999999999999999'
        style.pointerEvents = 'none'

        style.width = this.renderCanvas.width = this.computerCanvas.width = this.globalWidth
        style.height = this.renderCanvas.height = this.computerCanvas.height = this.globalHeight

        document.body.append(this.renderCanvas)

        window.addEventListener('mousedown', this.handleMouseDown.bind(this))
        window.addEventListener('pagehide', this.handlePageHide.bind(this))
    }

    run() {
        this.running = true
        if (this.booms.length == 0) {
            return this.running = false
        }

        requestAnimationFrame(this.run.bind(this))

        this.computerContext.clearRect(0, 0, this.globalWidth, this.globalHeight)
        this.renderContext.clearRect(0, 0, this.globalWidth, this.globalHeight)

        this.booms.forEach((boom, index) => {
            if (boom.stop) {
                return this.booms.splice(index, 1)
            }
            boom.move()
            boom.draw()
        })
        this.renderContext.drawImage(this.computerCanvas, 0, 0, this.globalWidth, this.globalHeight)
    }
}

const cursorSpecialEffects = new CursorSpecialEffects()
cursorSpecialEffects.init()