bahmutov

it('until the number 7 appears', () => {
    const checkAndReload = () => {
      // get the element's text, convert into a number
      cy.get('#result').should('not.be.empty')
      .invoke('text').then(parseInt)
      .then((number) => {
        // if the expected number is found
        // stop adding any more commands
        if (number === 7) {
          cy.log('lucky **7**')

bahmutov

```js
/// <reference types="Cypress" />
describe('intercept', () => {
  it('stubs anchor ping', () => {
    cy.visit('/')
    cy.intercept({
      method: 'POST',
      pathname: '/track'
    }, {}).as('ping')
    cy.get('a[ping]').click()

bahmutov

Keybase proof

I hereby claim:

• I am bahmutov on github.
• I am glebb (https://keybase.io/glebb) on keybase.
• I have a public key ASBM0WBon-OfVjLsNOuqvrPMbR0HNkjc9zdg42Sxp-K3kQo

To claim this, I am signing this object:

bahmutov

Printing wallclock timestamps and frame timestamps (since common start)

cypress:server:video 1.3989999294281006 frame 1.326711893081665 received screencastFrame +0ms
  cypress:server:video 1.5299999713897705 frame 1.4792709350585938 received screencastFrame +131ms
  cypress:server:video 2.922999858856201 frame 2.340052843093872 received screencastFrame +1s
Browserslist: caniuse-lite is outdated. Please run next command `npm update caniuse-lite browserslist`
  cypress:server:video 4.042999982833862 frame 2.4192519187927246 received screencastFrame +1s
  cypress:server:video 4.049000024795532 frame 2.584810972213745 received screencastFrame +7ms

bahmutov

// following along https://medium.com/@luijar/kliesli-compositions-in-javascript-7e1a7218f0c4
const R = require('ramda')
const Maybe = require('ramda-fantasy').Maybe

// parse JSON string into object
// parse :: String -> Object | Null
function parse(s) {
  try {
    return JSON.parse(s)
  } catch (e) {

bahmutov

• Boston new technology https://www.meetup.com/Boston_New_Technology/
• Mobile tea https://www.meetup.com/mobiletea/events/239566288/
• Startup grind https://www.meetup.com/Startup-Grind-Boston/
• Entrepreneurs + VCs https://www.meetup.com/bostonbusiness/
• Tech in Motion https://www.meetup.com/TechinmotionBoston/
• Boston TechBreakfast https://www.meetup.com/Boston-TechBreakfast/

Also recommended: http://productcampboston.org/ June 10, 2017

bahmutov

install

Install on Mac using brew install tmux and start with tmux

main commands

See help (list of commands) with Control-b ? key combination. Leave help view by pressing q key. From now on use Control-b (aka C-b) to start all tmux commands (C-b is called command prefix and can be changed, see tmux.config options).

bahmutov

• Marble diagrams are awesome and show the streams really well. When you cannot fit them due to space constraints - time to refactor
• Testing Rx.js code is still hard and requires controlling timing of events. See https://glebbahmutov.com/blog/testing-reactive-code/
• Reactive is all about controlling sequence of events. A simple operation might be take

In its first form it just takes N items s.take(2) which creates second stream with first 2 events from s and the completes. But what happens if you don't know how many items to take? Maybe there is a condition, a simple function that operates on the event data and/or global state that tells when to stop taking items. In this case takeWhile is useful s.takeWhile(x => x < 10)

bahmutov

Imagine I want to separate caching for offline support from other features. I would load first service worker to cache index.html and static resources in /static and would load second service worker to do other things.

<script>
    if ('serviceWorker' in navigator) {
      console.log('page is registering two service workers')
      // one.js should cache index.html and /static folder
 navigator.serviceWorker.register('one.js', {scope: './'})

bahmutov

A list of free online security scanning tools that help you quickly check your site against obvious weaknesses

• Observatory by Mozilla https://observatory.mozilla.org/ scans your website for missing security related server headers
• SSL Server Test https://www.ssllabs.com/ssltest/ tests the encryption strength of the SSL used in your https connection.
• CSP Evaluator https://csp-evaluator.withgoogle.com/ checks the security headers against XSS attacks