vant/lib/lazyload/vue-lazyload/listener.js

Mobile UI Components built on Vue

var __defProp = Object.defineProperty;
var __getOwnPropDesc = Object.getOwnPropertyDescriptor;
var __getOwnPropNames = Object.getOwnPropertyNames;
var __hasOwnProp = Object.prototype.hasOwnProperty;
var __export = (target, all) => {
  for (var name in all)
    __defProp(target, name, { get: all[name], enumerable: true });
};
var __copyProps = (to, from, except, desc) => {
  if (from && typeof from === "object" || typeof from === "function") {
    for (let key of __getOwnPropNames(from))
      if (!__hasOwnProp.call(to, key) && key !== except)
        __defProp(to, key, { get: () => from[key], enumerable: !(desc = __getOwnPropDesc(from, key)) || desc.enumerable });
  }
  return to;
};
var __toCommonJS = (mod) => __copyProps(__defProp({}, "__esModule", { value: true }), mod);
var stdin_exports = {};
__export(stdin_exports, {
  default: () => ReactiveListener
});
module.exports = __toCommonJS(stdin_exports);
var import_use = require("@vant/use");
var import_util = require("./util");
var import_utils = require("../../utils");
class ReactiveListener {
  constructor({
    el,
    src,
    error,
    loading,
    bindType,
    $parent,
    options,
    cors,
    elRenderer,
    imageCache
  }) {
    this.el = el;
    this.src = src;
    this.error = error;
    this.loading = loading;
    this.bindType = bindType;
    this.attempt = 0;
    this.cors = cors;
    this.naturalHeight = 0;
    this.naturalWidth = 0;
    this.options = options;
    this.$parent = $parent;
    this.elRenderer = elRenderer;
    this.imageCache = imageCache;
    this.performanceData = {
      loadStart: 0,
      loadEnd: 0
    };
    this.filter();
    this.initState();
    this.render("loading", false);
  }
  /*
   * init listener state
   * @return
   */
  initState() {
    if ("dataset" in this.el) {
      this.el.dataset.src = this.src;
    } else {
      this.el.setAttribute("data-src", this.src);
    }
    this.state = {
      loading: false,
      error: false,
      loaded: false,
      rendered: false
    };
  }
  /*
   * record performance
   * @return
   */
  record(event) {
    this.performanceData[event] = Date.now();
  }
  /*
   * update image listener data
   * @param  {String} image uri
   * @param  {String} loading image uri
   * @param  {String} error image uri
   * @return
   */
  update({ src, loading, error }) {
    const oldSrc = this.src;
    this.src = src;
    this.loading = loading;
    this.error = error;
    this.filter();
    if (oldSrc !== this.src) {
      this.attempt = 0;
      this.initState();
    }
  }
  /*
   *  check el is in view
   * @return {Boolean} el is in view
   */
  checkInView() {
    const rect = (0, import_use.useRect)(this.el);
    return rect.top < window.innerHeight * this.options.preLoad && rect.bottom > this.options.preLoadTop && rect.left < window.innerWidth * this.options.preLoad && rect.right > 0;
  }
  /*
   * listener filter
   */
  filter() {
    Object.keys(this.options.filter).forEach((key) => {
      this.options.filter[key](this, this.options);
    });
  }
  /*
   * render loading first
   * @params cb:Function
   * @return
   */
  renderLoading(cb) {
    this.state.loading = true;
    (0, import_util.loadImageAsync)(
      {
        src: this.loading,
        cors: this.cors
      },
      () => {
        this.render("loading", false);
        this.state.loading = false;
        cb();
      },
      () => {
        cb();
        this.state.loading = false;
        if (process.env.NODE_ENV !== "production" && !this.options.silent)
          console.warn(
            `[@vant/lazyload] load failed with loading image(${this.loading})`
          );
      }
    );
  }
  /*
   * try load image and  render it
   * @return
   */
  load(onFinish = import_utils.noop) {
    if (this.attempt > this.options.attempt - 1 && this.state.error) {
      if (process.env.NODE_ENV !== "production" && !this.options.silent) {
        console.log(
          `[@vant/lazyload] ${this.src} tried too more than ${this.options.attempt} times`
        );
      }
      onFinish();
      return;
    }
    if (this.state.rendered && this.state.loaded) return;
    if (this.imageCache.has(this.src)) {
      this.state.loaded = true;
      this.render("loaded", true);
      this.state.rendered = true;
      return onFinish();
    }
    this.renderLoading(() => {
      var _a, _b;
      this.attempt++;
      (_b = (_a = this.options.adapter).beforeLoad) == null ? void 0 : _b.call(_a, this, this.options);
      this.record("loadStart");
      (0, import_util.loadImageAsync)(
        {
          src: this.src,
          cors: this.cors
        },
        (data) => {
          this.naturalHeight = data.naturalHeight;
          this.naturalWidth = data.naturalWidth;
          this.state.loaded = true;
          this.state.error = false;
          this.record("loadEnd");
          this.render("loaded", false);
          this.state.rendered = true;
          this.imageCache.add(this.src);
          onFinish();
        },
        (err) => {
          !this.options.silent && console.error(err);
          this.state.error = true;
          this.state.loaded = false;
          this.render("error", false);
        }
      );
    });
  }
  /*
   * render image
   * @param  {String} state to render // ['loading', 'src', 'error']
   * @param  {String} is form cache
   * @return
   */
  render(state, cache) {
    this.elRenderer(this, state, cache);
  }
  /*
   * output performance data
   * @return {Object} performance data
   */
  performance() {
    let state = "loading";
    let time = 0;
    if (this.state.loaded) {
      state = "loaded";
      time = (this.performanceData.loadEnd - this.performanceData.loadStart) / 1e3;
    }
    if (this.state.error) state = "error";
    return {
      src: this.src,
      state,
      time
    };
  }
  /*
   * $destroy
   * @return
   */
  $destroy() {
    this.el = null;
    this.src = null;
    this.error = null;
    this.loading = null;
    this.bindType = null;
    this.attempt = 0;
  }
}