Porting nodejs module to React Native: Object.prototype undefined

Porting nodejs module to React Native: Object.prototype undefined -

  • Here’s my source tree at the exact moment of the problem: – – I believe , and will make it launch (note that onvif is not installed from npm but cloned in npm script and then installed, but it gets installed in with a symlink to the place where it…
  • I even tried to put everything in just in case, but the error persists).
  • Also don’t mind the extra docker things I have in the folder – – Anyways, the problem is: – – I’m trying to use the nodejs module onvif in React Native, so I used this technique to translate the require methods using babel and installed browserfy modules to implement the…
  • However, when I try to simply import the onvif module I get this: – – Here’s device.js line 30, looks like is undefined here – – When I import the which imports , nothing happens.
  • But then it imports which seems to be getting undefined when importing again – – I also tried this method which seems to avoid all the babel translation but surprisingly the problem persists.

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Accessing Nested Objects in JavaScript

  • tldr; safely access nested objects in JavaScript in a super cool way.
  • One of those things is the confrontation with this error when you try to access a nested object, – – Most of the times when we’re working with JavaScript, we’ll be dealing with nested objects and often we’ll be needing to access the innermost nested values safely.
  • But, for some reason, if our user’s personal info is not available, the object structure will be like this, – – Now if you try you access the name, you’ll be thrown Cannot read property ‘name’ of undefined.
  • The usual way how most devs deal with this scenario is, – – This is okay if your nested structure is simple, but if you have your data nested 5 or 6 levels deep, then your code will look really messy like this, – – There are a few tricks…
  • Unfortunately, you cannot access nested arrays with this trick – – Array reduce method is very powerful and it can be used to safely access nested objects.

Accessing nested objects in JavaScript without getting choked by ‘cannot read property of undefined’ error
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React: Working with APIs – Manny Henri

Just released a new #course on #reactjs Working with #APIs  #javascript #Developer

  • While React simplifies the challenge of making API calls, figuring out how best to structure your application around an API is more difficult.
  • There are two primary approaches: using the React built-in fetch methods, or using axios, a promise-based library.
  • Instructor Emmanuel Henri covers the basic concepts behind REST APIs and shows how to build reusable components that use fetch methods to call real-world APIs like News API.
  • He then shows how to connect to APIs using axios, which simplifies API calls by automatically transforming JSON data.
  • By the end of the course, you should have the skills to structure API calls, maintain state, and make users happy.

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A tiny expression compiler for React Native Animated values

  • Its expressive API lets developers compose animated effects based on time, spring physics and even real-time user interaction with distinct ease.I’ve recently released animated.macro, a small JavaScript package that improves the ergonomics of working with animated values in React Native apps — and, more importantly, has been fun to build.
  • The results of these operations can then be used anywhere the basic values can.For instance, here’s how you add two animated values together:const result = Animated.add(x, y);And here’s a slightly more involved calculation:const result = Animated.modulo( Animated.add(phase, Math.PI * 2 + angle), Math.PI * 2);What can be improvedOn closer inspection, the…
  • This can be an inconvenience when refactoring animation code.In the second example, the types of phase and angle (and of Math.PI) similarly dictate the shape of the surrounding code — e.g. Animated values can’t be added with + and plain numbers can’t be added with Animated.add().
  • Can we do better?Yes.Introducing animated.macro 🕺🏽🔢animated.macro lets you write JS-like arithmetic expressions that operate on animated values and plain numbers alike.
  • These expressions take the form of tagged template literals that evaluate to animated values.The second example above can now be written as:import animated from “animated.macro”;const result = animated` (${phase} + ${Math.PI} * 2 + ${angle}) % (${Math.PI} * 2)`;Addition, subtraction, multiplication, division and modulo are all supported, with the same…

The Animated library, which allows animations to be set up in JS and executed on the native thread, is a mainstay of the React Native programming model. Its expressive API lets developers compose…
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React Lifecycle, Quickly by the Method – Gabriel Kunkel – Medium

React Lifecycle, Quickly by the Method  #javascript #react #reactjs

  • React Lifecycle, Quickly by the MethodThese methods aren’t perfectly desirable to use, but they’re a way of exerting more control over the situation when the rest of the world just doesn’t want to cooperate with React.componentWillMount: Use for connecting to API’s on root components or containers.
  • componentDidMount: Load your data and do anything you need to do to a component.
  • After a parent component did some value changing.
  • This is the place to change outside DOM things in respect to changes that are linked up to the values tracked by react.
  • If you’re going to kill your component, this is the place where you clean-up everything that react won’t clean up on its own, including network requests, event listeners, and a canvas box.The whole cycle with methods.

These methods aren’t perfectly desirable to use, but they’re a way of exerting more control over the situation when the rest of the world just doesn’t want to cooperate with React.
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The Life Cycle Recap · react-indepth

#reactjs lifecycle flowchart by @pbesh from

  • We have now worked through the three phases of the React life cycle: Birth/Mounting, Growth/Update and finally Death/Unmount.
  • By having these phases and corresponding methods React provides us a clear path for developing Components.
  • These phases also allow us to begin to optimize our Components and our entire application.
  • To review, the methods and order called are:

    In addition, this flow chart by Peter Beshai breaks down the different methods and also calls out when is safe and NOT safe to call:

We have now worked through the three phases of the React life cycle: Birth/Mounting, Growth/Update and finally Death/Unmount. By having these phases and corresponding methods React provides us a clear path for developing Components. These phases also allow us to begin to optimize our Components and our entire application.
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Positive Reactions: Developing With React.js

A short article about development with React Native! #reactnative #AppDev

  • React Native allows you to create React components that directly translate to native components.
  • While development with other non-native frameworks also involve JavaScript, they tend to run in a webview embedded in a native app, further complicating the process.
  • Its sister project, React Native, offers app developers the ability to create native apps using only JavaScript.
  • Too often, existing frameworks talk about making an app seem native to both platforms, only for resulting apps to feel like they belong on neither.
  • With React Native’s view declarations, it becomes much easier to manage any possible contingency when users operate your app.

React Native gives developers a native app development tool that does a great job of bridging the gap between Android and iOS projects.
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Testing React apps with Nightwatch

Testing #ReactJS apps E2E is simple with Nightwatch  - #developers #javascript

  • have the browser to open before all tests from this file, and then closed after the tests are finished they are finished
  • Now the before() hook will take care of login steps and the after() hook will close the browser when all tests from this file are done.
  • Since we have the command ready, we will want to use it in a test.
  • Once your test suite gets bigger, you’ll notice steps within your tests that could be abstracted away and reused across your project.
  • writing the test in Page Object Pattern methodology

Read the full article, click here.


@Syncano: “Testing #ReactJS apps E2E is simple with Nightwatch – #developers #javascript”


In this part of Testing React Apps with Nightwatch, I’ll talk about expanding your test framework with before() and after() hooks as well as custom commands


Testing React apps with Nightwatch

Using ES2016 Decorators in React Native

POSTED: How to use #ES2016 decorators in #ReactNative with @stan229   @reactjs #esnext

  • Using Decorators in React Native
  • Let’s see how we would go about using @autobind or any other decorator in our React Native application.
  • You can read more about decorators and see the proposal .
  • Using decorators allows us to extend a function (class or property) by wrapping a function (decorator) around it.
  • Experimental support of decorators is also available in TypeScript .

Read the full article, click here.


@ModusCreate: “POSTED: How to use #ES2016 decorators in #ReactNative with @stan229 @reactjs #esnext”


Decorators are an excellent feature brought over from languages like Python and Java. Stan Bershadskiy shows how to use them in React Native.


Using ES2016 Decorators in React Native

Listen and Learn

Listen and Learn - React.js with Andrew DelPrete r1g9LNmSS #ReactJS
☞

  • Share around anything related to programming including Java, JavaScript, PHP, C/C++, .Net, Node.js, Python, Ruby, iOS, Android, Database, Shell Scripting, UI/UX and more…

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@reactjs__dev: “Listen and Learn – React.js with Andrew DelPrete r1g9LNmSS #ReactJS
☞”



Listen and Learn