| import { progress } from '../../progress' |
|
|
| import type { OnScrollCallback } from './index' |
|
|
| const SCROLL_KEYS = { |
| x: { |
| length: 'Width', |
| position: 'Left', |
| }, |
| y: { |
| length: 'Height', |
| position: 'Top', |
| }, |
| } as const |
|
|
| |
| |
| |
| |
| export interface ScrollAxis { |
| current: number |
| progress: number |
| scrollLength: number |
| } |
|
|
| export interface ScrollInfo { |
| time: number |
| x: ScrollAxis |
| y: ScrollAxis |
| } |
|
|
| |
| |
| |
| export class ScrollHandler { |
| protected callback: OnScrollCallback |
| protected container: HTMLElement |
| protected info: ScrollInfo |
|
|
| constructor(callback: OnScrollCallback, container: HTMLElement) { |
| this.callback = callback |
| this.container = container |
|
|
| this.info = { |
| time: 0, |
| x: this.createAxis(), |
| y: this.createAxis(), |
| } |
| } |
|
|
| private createAxis = (): ScrollAxis => ({ |
| current: 0, |
| progress: 0, |
| scrollLength: 0, |
| }) |
|
|
| private updateAxis = (axisName: keyof Pick<ScrollInfo, 'x' | 'y'>) => { |
| const axis = this.info[axisName] |
| const { length, position } = SCROLL_KEYS[axisName] |
|
|
| axis.current = this.container[`scroll${position}`] |
| axis.scrollLength = |
| this.container[`scroll${length}`] - this.container[`client${length}`] |
|
|
| axis.progress = progress(0, axis.scrollLength, axis.current) |
| } |
|
|
| private update = () => { |
| this.updateAxis('x') |
| this.updateAxis('y') |
| } |
|
|
| private sendEvent = () => { |
| this.callback(this.info) |
| } |
|
|
| advance = () => { |
| this.update() |
| this.sendEvent() |
| } |
| } |
|
|
