开发一个vue自定义指令的npm库-系列二：如何同时支持vue2、vue3实例的typescript类型

╰+攻爆jí腚メ 2024-03-22 12:34 44阅读 0赞

vue2、vue3中绑定自定义vue指令的用法是不一样的，vue2是绑定到Vue上，而vue3是绑定到createApp返回的vue实例上，所以typescript类型自然也不一样

import Vue from "vue";
    import App from "./App.vue";
    
    import {
         svgWheel, svgDrag } from "svg-zoom-drag-vue-directives";
    svgWheel(Vue);
    svgDrag(Vue);
    
    new Vue({
        
      render: (h) => h(App),
    }).$mount("#app");

import {
         createApp } from "vue";
    import App from "./App.vue";
    
    import {
         svgWheel, svgDrag } from "svg-zoom-drag-vue-directives";
    const app = createApp(App);
    svgWheel(app);
    svgDrag(app);
    
    app.mount("#app");

那么，问题来了

#### 如何同时支持vue2、vue3实例的typescript类型 ####

经过调研，我使用vue-demi这个库，vue-demi会根据当前项目vue版本，从其定义的不同vue版本的模块导入模块，从而ts类型也会指向不同定义

import {
         Vue2, App } from "vue-demi";

如果当前项目是vue2，`Vue2`指向的是本地项目中vue的Vue2类型，则typeof Vue2就能取到正确类型，`App`会指向vue-demi定义的vue3版本中的App类型，使用重载写法来缩小范围，根据传参，最终类型会是`typeof Vue2`

如果当前项目是vue3，`Vue2`类型会指向vue-demi定义的vue3版本中的`any`类型，`App`会指向本地项目中vue的App类型，使用重载写法来缩小范围，根据传参，最终类型会是`App<Element>`

这样就可以实现同时支持vue2、vue3实例的typescript类型，有更好的写法也可以分享一下

import {
         Vue2, App } from "vue-demi";
    
    /** create a `v-svgWheel` directive for a Vue app, allows the user to control the zoom in and out of an SVG image using the mouse wheel. */
    export function svgWheel(app: typeof Vue2): void;
    /** create a `v-svgWheel` directive for a Vue app, allows the user to control the zoom in and out of an SVG image using the mouse wheel. */
    export function svgWheel(app: App<Element>): void;
    // Control the zoom in and out of an SVG image by setting the viewbox attribute of the SVG element. The third parameter of the viewbox controls the horizontal size, while the fourth parameter sets the vertical size.
    export function svgWheel(app: typeof Vue2 | App<Element>) {
        
      app.directive("svgWheel", (el: HTMLElement) => {
        
        if (el) {
        
          el.onwheel = (e: WheelEvent) => {
        
            // Because the SVG is rendered using v-html, the child element of the bound DOM is the SVG element.
            const svgDom = el.firstChild as SVGSVGElement;
            const viewBox = svgDom.getAttribute("viewBox") as string;
            const [x, y, width, height] = viewBox.split(/\s+/).map(parseFloat);
            // event.wheelDelta has been deprecated, use event.deltaY instead.
            // event.deltaY returns a positive value when scrolling downwards and a negative value when scrolling upwards. Otherwise, it is 0. event.wheelDelta is the opposite.
            const scaleDelta = e.deltaY > 0 ? 0.9 : 1.1; // Zoom scale.
            const newWidth = width * scaleDelta;
            const newHeight = height * scaleDelta;
            // Calculate the centering offset.
            const dx = (width - newWidth) / 2;
            const dy = (height - newHeight) / 2;
            const newViewBox = `${
          x + dx} ${
          y + dy} ${
          newWidth} ${
          newHeight}`;
            svgDom.setAttribute("viewBox", newViewBox);
          };
        }
      });
    }
    
    /** create a `v-svgDrag` directive for a Vue app, allows the user to drag the SVG image by holding down the mouse and moving the cursor. */
    export function svgDrag(app: typeof Vue2): void;
    /** create a `v-svgDrag` directive for a Vue app, allows the user to drag the SVG image by holding down the mouse and moving the cursor. */
    export function svgDrag(app: App<Element>): void;
    // Control the drag of an SVG image by setting the "viewBox" attribute of the SVG element. The first parameter of "viewBox" controls the left-right position, and the second parameter sets the up-down position.
    export function svgDrag(app: typeof Vue2 | App<Element>) {
        
      app.directive("svgDrag", (el: HTMLElement) => {
        
        let clientX = 0; // The last x-axis position of the mouse
        let clientY = 0; // The last y-axis position of the mouse
        let debounce = true; // Throttling is necessary, otherwise the dragging effect will appear jerky
        let isStartMoveSvg = false; // Whether to start dragging
        let ratio = 1; // The ratio of drag speed to size
        let sgvDom: SVGAElement; // The SVG element
        let viewBox: string; // The "viewBox" attribute of the SVG element
        let arrPoint: number[]; // The value of the "viewBox" attribute of the SVG element
        // Mouse down means start moving
        el.onmousedown = () => {
        
          isStartMoveSvg = true;
          const width = el.getBoundingClientRect().width;
          // Because the SVG is rendered using "v-html", the child element of the bound command DOM is the SVG element
          sgvDom = el.firstChild as SVGAElement;
          viewBox = sgvDom.getAttribute("viewBox") as string;
          arrPoint = viewBox.split(/\s+/).map(parseFloat);
          // Dynamically adjust the drag speed based on the size, otherwise it becomes harder to drag as the SVG becomes smaller
          ratio = arrPoint[2] / width;
          if (ratio < 1) ratio = 1;
        };
        // Mouse up means end moving
        el.onmouseup = () => {
        
          isStartMoveSvg = false;
          clientX = 0;
          clientY = 0;
        };
        // Dynamically set "viewBox" while moving
        el.onmousemove = (e: MouseEvent) => {
        
          if (debounce) {
        
            debounce = false;
            if (isStartMoveSvg) {
        
              if (clientX !== 0 && clientY !== 0) {
        
                arrPoint[0] = arrPoint[0] - (e.clientX - clientX) * ratio;
                arrPoint[1] = arrPoint[1] - (e.clientY - clientY) * ratio;
                sgvDom.setAttribute("viewBox", arrPoint.join(" "));
              }
              clientX = e.clientX;
              clientY = e.clientY;
            }
            setTimeout(() => {
        
              debounce = true;
            }, 50);
          }
        };
      });
    }