elementIsEnabled.js

let    webdriver = require('selenium-webdriver'),
        chrome = require('selenium-webdriver/chrome'),
        By = webdriver.By
        until = webdriver.until;

let options = new chrome.Options();
options.setChromeBinaryPath('/Applications/Google\ Chrome\ Canary.app/Contents/MacOS/Google\ Chrome\ Canary');
options.addArguments(['headless','disable-gpu']);

let driver = new webdriver.Builder().forBrowser('chrome').setChromeOptions(options).build();

let baseURL = 'https://www.google.com';

driver.get(baseURL)

//ref:  http://seleniumhq.github.io/selenium/docs/api/javascript/module/selenium-webdriver/lib/until.html
let button = driver.wait(() => {
    return driver.findElement({name:'btnK'}).isEnabled()
}).then(() => {
    driver.findElement({name:'btnK'}).click()
})

// returns:  
//  .../node_modules/selenium-webdriver/lib/promise.js:2634
//        throw error;
//        ^
//
//TypeError: element.isEnabled is not a function