Anthony Gore

In this article, dive deep into the strengths and weaknesses of both REST and GraphQL so you can decide which API architecture is best for your next project.

April 25, 2022

Using HTML, and a little bit of Pug, this web dev expert shows us how to extend the components of our Vue.js applications.

Updated February 10, 2020

Tired of the baggage that comes along with using jQuery in your development projects, such as increased size and trick configurations? Use Vue.js instead.

Updated February 10, 2020

Having a hard time deciding on which method to use to define your component template? Read on for some great tips from a Vue.js expert.

Updated February 10, 2020

A Vue.js whiz explains how to create different kinds of browser navigation using this powerful JavaScript framework. Read on for more!

Updated February 10, 2020

In this article, we'll explore how pre-rendering works with Vue.js and look at two examples; one with a Node.js project, one with a Laravel project.

Updated February 10, 2020

If you're looking to give your Vue.js-based web application a little bit of an enhancement, read on to see how Webpack can help with that.

Updated February 10, 2020

In this article, a DZone MVB and Vue.js expert shows three methods you can use for architecting an app for code splitting using Vue and Webpack.

Updated February 10, 2020

Ever been reading a comment section of a site and wonder how they make that collapsible, indented style view? Read on to find out!

Updated February 10, 2020

Learn how to restrict user permissions using Vue.js and an open source JavaScript library so users of your can, say, post a comment but not delete a comment.

Updated February 10, 2020

To test a component in isolation you can replace it's children components by stubbing them. Vue Test Utils can automatically do this for you with a feature called shallowMount. But what happens if a component is tightly coupled to one of its children? You can still use shallowMount, but you'll then have to selectively "unstub" the tightly coupled child. In this article, I'll show you how to use stubbing to write simpler unit tests. Note: this article was originally posted here on the Vue.js Developers blog on 2019/09/30. Testing in isolation A key idea of unit testing is to test a "unit" of the application in isolation. In component-based frontend apps, we consider the "unit" to be a component. Testing a component in isolation ensures that tests are unaffected by dependencies and other influences of children components. To isolate a component from surrounding components, you can stub it's children components. The diagram below shows how stubbing this way would affect a typical component hierarchy. Stubbing a component usually means replacing it with a simple "stand in" component with no state, logic, and a minimal template. For example, you might replace this: export default { name: "MyComponent", template: "..." props: { ... }, methods: { ... }, computed: { ... } ... }; with this: export default { name: "MyComponentStub" template: "" }; Rather than manually stubbing children components, though, Vue Test Utils offers the shallowMount feature which does it automatically. Coupled components In the real world, components aren't always completely decoupled. Sometimes a component relies on a child component and so the child can't be stubbed without losing some functionality. For example, say we make a button with a cool animation, and we want to reuse it across an app, and so we decide to create a custom component called animated-button. We now have the my-form component that uses this button component. It's been implemented such that my-form is coupled to animated-button, since the latter emits a "click" event that's used to trigger the submit method in the former. MyForm.vue Unit testing my-form Another key idea of unit testing is that we want to test the inputs and outputs of the unit and consider the internals to be a black box. In the my-form component, we should make a unit test where the input is the click of the button, while the output is the Vuex commit. We'll call this test "should commit FORM_SUBMIT when button clicked". We'll create it by first shallow mounting MyForm to isolate it from the influence of any children components as previously prescribed. MyForm.spec.js import { shallowMount } from "@vue/test-utils"; import MyForm from "@/components/MyForm"; describe("MyForm.vue", () => { it("should commit FORM_SUBMIT when button clicked", () => { const wrapper = shallowMount(MyForm); }); }); Next, we'll use the wrapper find API method to find the button component. We pass a CSS selector "animated-button" as the locator strategy. We can then chain the trigger method and pass "click" as the argument. This is how we generate the input of the test. We can then assert that a Vuex commit gets made (probably using a spy, but that's not relevant to this article so I won't detail it). MyForm.spec.js it("should commit FORM_SUBMIT when button clicked", () => { const wrapper = shallowMount(MyForm); wrapper.find("animated-button").trigger("click"); // assert that $store.commit was called }); If we try to run that, we'll get this error from Vue Test Utils: find did not return animated-button, cannot call trigger() on empty Wrapper Is the CSS selector wrong? No, the issue is that we shallow mounted the component, so all the children were stubbed. The auto-stub process changes the name of AnimatedButton to "animated-button-stub" in the template. But changing the selector from "animated-button" to "animated-button-stub" is not a solution. Auto-stubs have no internal logic, so the click event we trigger on it is not being listened to anyway. Selective unstubbing We still want to shallow mount my-form, as we want to ensure it's isolated from the influence of its children. But animated-button is an exception as it's functionality is required for the test. Vue Test Utils allows us to specify the stub for a particular component rather than using an auto-stub when shallow mounting. So the trick is to "unstub" animated-button by using its original component definition as the stub so it retains all of its functionality! To do this, let's import the AnimatedButton component at the top of the file. Now, let's go to our test and create a const stubs and assign it an object. We can put AnimatedButton as an object property shorthand. Now, we'll pass in stubs as part of our shallow mount config. We'll also replace the CSS selector with the component definition, as this is the preferred way of using the find method. MyForm.spec.js import { shallowMount } from "@vue/test-utils"; import MyForm from "@/components/MyForm"; import AnimatedButton from "@/component/AnimatedButton" describe("MyForm.vue", () => { it("should commit FORM_SUBMIT when button clicked", () => { const stubs = { AnimatedButton }; const wrapper = shallowMount(MyForm, { stubs }); wrapper.find(AnimatedButton).trigger("click"); ... }); }); Doing it this way should give you a green tick. Wrap up You always want to isolate your components in a unit test, which can easily be achieved by stubbing all the children components with shallowMount. However, if your component is tightly coupled with one of its children, you can selectively "unstub" that component by providing the component definition as a stub and overriding the auto-stub. Become a senior Vue developer in 2020. Learn and master what professionals know about building, testing, and deploying, full-stack Vue apps in our latest course. Learn more

February 7, 2020

Learn how to programmatically identify any CSS that's slowing down your web application, and how to minimize it to speed up load times.

Updated February 5, 2020

If you're caught trying to decide between these two great JavaScript frameworks, read on to get a Vue advocate's opinion on the matter.

Updated February 4, 2020

Learn how Vue.js and Webpack can be used to split a single page app into more optimally sized files that can be dynamically loaded.

Updated February 4, 2020

Browser support for native JavaScript modules is finally happening. In this article, we show you what this means for Vue.js developers.

Updated February 4, 2020

In this post, we'll look at a design pattern that makes it easy to inject initial application state into the head of the HTML page, and allows for a lot of flexibility.

Updated February 4, 2020

A Vue.js expert demonstrates different AJAX patterns that can be used with Vue.js and Vuex, and gives some sample JavaScript code for each example.

Updated February 4, 2020

While some people are still not sold on the use of JSX in their JavaScript, it has several benefits which we'll explore in this article.

Updated February 4, 2020

Using Laravel as the backend for your Vue.js application is a new advantage. Read on to learn how to use these two frameworks to handle SSR.

Updated February 4, 2020

In this article, we go over the code required to add JavaScript libraries to your Vue project, as well as the ways you definitely shouldn't.

Updated February 4, 2020

While Vue developers may cringe at the thought, sometimes it's necessary to use jQuery with your Vue.js app. Learn how here!

Updated February 4, 2020

Rails, Express, Django... the list goes on. There are so many great backed frameworks, which one should you choose? If you use Vue, read on for one expert's opinion.

Updated January 24, 2020

A dev looks at resources for Vue developers working with SPAs, Webpack, authentication, GraphQL, documentation, and testing.

Updated January 24, 2020

In this post, a Vue.js expert and web dev extraordinaire provides a tutorial on using a new wrapper library for Vue to create web components.

Updated January 17, 2020

This can be a bit of a pain, but this Vue.js expert shows us how it's done.

Updated January 17, 2020

If your app is targeting a global user base, then you may run into issues where the iframe you've embedded doesn't render for all users.

Updated January 6, 2020

It might sound a little weird at first, but if there's anyone who knows how to do it, it's this Vue developers. Read on for some expert JavaScripting!

Updated January 6, 2020