问量角器:如何在阴影DOM (聚合物)中选择多层阴影根下的输入元素

EN

class HomePage {
   get shadowRoot(): ElementFinder {
        return element(
            By.js(function (elem) {
                try {
                    // querySelectorAll returns array-like object, so converting it to Array with this:
                    return Array.prototype.slice.call(
                        document.querySelector(elem).shadowRoot.querySelectorAll('#mdr-ibe')
                    );
                } catch (err) {
                    // using try/catch to avoid uncaught errors
                    return [];
                }
            }, 'css-locator-of-element-with-shadow-root')
        );
    }

    public async startSearch() {
        // Using chaining to search for elements inside shadowRoot:
        const startSearchButton = this.shadowRoot.$('button.start-search')
        await browser.wait(EC.elementToBeClickable(startSearchButton));
        await startSearchButton.click();
    }
}