Class V8CustomElement

deps/v8/tools/js/web-api-helper.mjs:7–50

import {delay, formatBytes} from './helper.mjs';

export class V8CustomElement extends HTMLElement {
  _updateTimeoutId;
  _updateCallback = this.forceUpdate.bind(this);

  constructor(templateText) {
    super();
    const shadowRoot = this.attachShadow({mode: 'open'});
    shadowRoot.innerHTML = templateText;
  }

  $(id) {
    return this.shadowRoot.querySelector(id);
  }

  querySelectorAll(query) {
    return this.shadowRoot.querySelectorAll(query);
  }

  requestUpdate(useAnimation = false) {
    if (useAnimation) {
      window.cancelAnimationFrame(this._updateTimeoutId);
      this._updateTimeoutId =
          window.requestAnimationFrame(this._updateCallback);
    } else {
      // Use timeout tasks to asynchronously update the UI without blocking.
      clearTimeout(this._updateTimeoutId);
      const kDelayMs = 5;
      this._updateTimeoutId = setTimeout(this._updateCallback, kDelayMs);
    }
  }

  forceUpdate() {
    this._updateTimeoutId = undefined;
    this._update();
  }

  _update() {
    throw Error('Subclass responsibility');
  }

  get isFocused() {
    return document.activeElement === this;
  }
}

export class FileReader extends V8CustomElement {
  constructor(templateText) {