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Building a Desktop App with Vue: NW.js

n_tepluhina profile image Natalia Tepluhina ãƒģUpdated on ãƒģ8 min read

Previously I've written two articles about building desktop applications with Vue framework: one for Vuido library and one for Electron. I've had some comments requesting an article about NW.js and I promised to write one... and here we go! Better late than never 😅

NW.js (previosly known as node-webkit) is a framework for building desktop applications with HTML, CSS, and JavaScript. It's based on Chromium and Node.js. NW.js lets you call Node.js code and modules directly from browser and also use Web technologies in your app. Further, you can easily package a web application to a native application.

⚛ī¸ Differences from Electron

Electron and NW.js share many features: they are both built on top of Chromium and Node.js and use HTML, CSS and JS for building a desktop app. But they also have some notable differences:

  • In NW.js the main entry point of an application is a web page or a JS script. You specify this entry via package.json main property. In Electron, the entry point is a JavaScript script. Instead of providing a URL directly, you manually create a browser window and load an HTML file using the API.
  • On build process NW.js builds all Chromium; Electron uses libchromiumcontent to access Chromium's Content API
  • NW.js has built-in support for compiling your source code to protected binaries. Electron is packaging its applications with asar, which contains the applications' unprotected source code.

đŸ’ģ What are we going to build

Now when we understand differences with Electron, we're going to build the same application as in the previous article: an app to check the weather in the city of user's choice built on top of OpenWeatherMap API. This project will be built with Vue CLI and I recommend this way to scaffold any Vue application.

If you want just to check the final NW.js app code, it's here.

🛠ī¸ Installation

Creating an app with Vue CLI

First, let's scaffold an app with Vue CLI. Please make sure you have installed it with typing the following command in your console:

vue --version

If you don't have a version or it's less than 3.x, please run

npm install -g @vue/cli

Now you can create a Vue project from the console! To do so, please run

vue create <<YOUR-PROJECT-NAME>>

and select options you need. I will use the default setup for this project.

Great, now we're ready to add some desktop magic 🧙

Adding NW.js

NW.js official documentation recommends to use one of two builders to package your application:

I chose nwjs-builder-phoenix and I will describe further steps assuming you will use it as well 😅

So, first you need to add it as a dependency to your project:

npm install --save-dev nwjs-builder-phoenix
## OR
yarn add --dev nwjs-builder-phoenix

Now you need to modify your package.json file to provide a correct entry for the packager.

Tip: you can find package.json in the root folder of your application.

Packager entry should be specified under the main property. We're going to run a development environment on the desktop so let's extend our package.json with the following:

"main": "http://localhost:8080"

It's the port where our scaffolded web application is running locally. Usually main is index.html but now we want to have a hot reload on every application change. That's why we're pointing main to a Vue application with hot reload module.

Running an application

Now let's run our web application:

npm run serve
## OR
yarn serve

You can check http://localhost:8080 in your browser to make sure an app is actually running. There should be something like this:

Application in browser

And finally we're ready to start a desktop app:

./node_modules/.bin/run .

This will fetch a specified version of NW.js (by default it's sdk) and run a development environment.

run is a command added by nwjs-builder-phoenix and dot means we're usind the package.json from the root directory.

Now you should have an application running on desktop

Application on desktop

Let's automate running dev environment a bit. Close your desktop app and install the NW.js SDK flavor:

npm install --save-dev nw@sdk
## OR
yarn add --dev nw@sdk

Now, add a new task to package.json scripts section:

"scripts": {
  "serve": "vue-cli-service serve",
  "build": "vue-cli-service build",
  "nw-serve": "nw ." /* <--- here is your new npm task */
},

Let's try to run it:

npm run nw-serve
## OR
yarn nw-serve

You should have your app running on desktop again but no downloading step now 🎉

Good news: you can simply open devtools like you do in the browser and use them to debug your application! Just click Window -> Devtools

Dev Tools

🕹ī¸ Scaffolding an app

Similarly to Electron, NW.js-powered application is built like a usual web application, so we're going to create a web app, style it with some CSS and let nwjs-builder-phoenix to care about packaging it to desktop application.

NOTE: Same as for Electron app, I didn't install any CSS framework or component library on purpose: I wanted to compare package size without adding any different dependencies. The only library used for all desktop projects is axios.

Open App.vue file and replace its content with the following code:

<template>
  <div id="app">
    <p>Enter the city name to check current weather in it</p>
    <section class="weather-input">
      <input type="text" v-model="query">
      <button :disabled="!query.length">Check</button>
    </section>
  </div>
</template>

<script>
export default {
  data() {
    return {
      query: "",
    };
  }
};
</script>

<style>
#app {
  font-family: "Avenir", Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-align: center;
  color: #2c3e50;
  margin-top: 60px;
}

.button {
  color: #000;
}
</style>

Now our application looks this way:

Unstyled app

🔗 Making an API call

I used the OpenWeatherMap current weather API. It gives you a lot of different information, you can check an example of JSON response here.

We're going to use axios to make API calls. Obviously, we need to install it:

npm install axios
## OR
yarn add axios

To be able to use axios inside any Vue component we will import it to main.js, set the base URL and then create a property in Vue prototype for it:

//main.js

import axios from 'axios'

axios.defaults.baseURL = 'http://api.openweathermap.org/data/2.5';
Vue.http = Vue.prototype.$http = axios;

Now in the App.vue we will create a bunch of data properties to display different weather data:

// App.vue

data() {
    return {
      query: '',
      error: false,
      city: '',
      country: '',
      weatherDescription: '',
      temp: null,
      tempMin: null,
      tempMax: null,
      humidity: null,
      icon: '',
    };
},

Similarly to Electron, I've added one additional property comparing to Vuido version and it's an icon. API provides a weather icon but we couldn't use it in Vuido app because currently there is no support for displaying images.

Let's also create a method to fetch our data:

methods: {
  showWeather() {
    this.$http
      .get(`/weather?q=${this.query}&units=metric&&appid=${API_KEY}`)
      .then(response => {
        this.city = response.data.name;
        this.country = response.data.sys.country;
        this.weatherDescription = response.data.weather[0].description;
        this.temp = response.data.main.temp;
        this.tempMin = response.data.main.temp_min;
        this.tempMax = response.data.main.temp_max;
        this.humidity = response.data.main.humidity;
        this.icon = `http://openweathermap.org/img/w/${
          response.data.weather[0].icon
        }.png`;
        this.error = false;
      })
      .catch(() => {
        this.error = true;
        this.city = '';
      });
  },
},

Don't forget to create a const API_KEY with your OpenWeather API key!

and add it to the click callback of our button:

<button :disabled="!query.length" @click="showWeather">Check</button>

Now if you enter the text into an input field and click the button, you can observe the API call in the Network tab:

API call response

💅 Displaying weather data

Let's add this data to the template:

<template>
  <main id="app">
    <p>Enter the city name to check current weather in it</p>
    <section class="weather-input">
      <input type="text" v-model="query">
      <button :disabled="!query.length" @click="showWeather">Check</button>
    </section>
    <section v-if="error" class="weather-error">
      There is no such city in the database
    </section>
    <section v-if="city.length" class="weather-result">
      <h1>{{city}}, {{country}}</h1>
      <p><em>{{weatherDescription}}</em></p>
      <div class="weather-result__main">
        <img :src="icon" alt="Weather icon">
        <div class="weather-result__temp">
          {{temp}}&deg;C
        </div>
      </div>
      <div class="weather-result__details">
        <p>Min: {{tempMin}}&deg;C</p>
        <p>Max: {{tempMax}}&deg;C</p>
        <p>Humidity: {{humidity}}%</p>
      </div>
    </section>
  </main>
</template>

Our application view:

App without styling

It still looks too basic, so it's time to add some CSS. Let's replace the whole style section of App.vue with the following code:

<style>
* {
  margin: 0;
  padding: 0;
}
html,
body,
#app {
  height: 100%;
}

#app {
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  padding: 10px;
  background: rgb(212, 228, 239);
  background: radial-gradient(
    ellipse at center,
    rgba(212, 228, 239, 1) 0%,
    rgba(134, 174, 204, 1) 100%
  );
  filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#d4e4ef', endColorstr='#86aecc',GradientType=1 ); /* IE6-9 fallback on horizontal gradient */
}

.weather-input {
  display: flex;
  align-items: center;
  padding: 20px 0;
}

.weather-result {
  text-align: center;
}

.weather-result__main {
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: 5px;
  font-size: 1.3rem;
  font-weight: bold;
}

.weather-result__details {
  display: flex;
  align-items: center;
  justify-content: space-around;
  color: dimgray;
}

.weather-error {
  color: red;
  font-weight: bold;
}

input {
  width: 75%;
  outline: none;
  height: 20px;
  font-size: 0.8rem;
}

button {
  display: block;
  width: 25%;
  height: 25px;
  outline: none;
  border-radius: 5px;
  white-space: nowrap;
  margin: 0 10px;
  font-size: 0.8rem;
}
</style>

And finally we have a beautiful fully-functional app:

App ready

The last thing to do before packaging it is to reduce a window size. To do so, we need to add a window property to package.json:

"window": {
  "width": 600,
  "height": 400
},

đŸ“Ļ Packaging

To package a NW.js app with nwjs-builder-phoenix you need to run a build command with a proper set of parameters. I am going to build it on for Mac to compare its size with Electron and Vuido apps.

First, we need to specify a NW.js version to be used on build process. We can do it via build property of package.json

"build": {
  "nwVersion": "0.35.3"
},

And then let's run a build command in the terminal:

./node_modules/.bin/build --tasks mac-x64 .

Again, dot in the command means we're using a package.json file located in the root project folder

Let's check a package size... 233 MB 😱!

App size

Wow, that's a lot. It's even bigger than Electron application!

🌟 Conclusions

Pros:

  • really easy to start
  • can be customized via CSS styling
  • good docs
  • has a support for protected binaries

Cons

  • very big package size
  • not-so-good naming (maybe it's just me but Electron/Vuido is way more memorable than NW.js)
  • small ecosystem.

💖 Special thanks

I want to thank Jared Wilcurt who helped me with answers on my NW.js questions. Jared is an author for NW.js Vue devtools to debug a Vue application right on the desktop.

UPDATE: If you wonder how to reduce the size of the package significantly, here is an article by Jared Wilcurt.

Discussion

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thejaredwilcurt profile image
The Jared Wilcurt

Thanks for covering NW.js, Natalia!

I got your "233 MB" app down to a 20 MB Windows installer (61.5 MB once installed). Available here:

If your goal is to have the same functionality as Electron, but at a considerably smaller filesize. NW.js offers that option.

It also offers the ability to have much more functionality and features, including access to the latest versions of Node and Chromium within 24 hours of a new release of either. Of course if you want the latest and greatest, it will be a big file size. That's the trade-off.

I just finished writing an article on how to reduce the filesize for an NW.js app, if anyone would like the secrets of turning a 233 MB app into a 20MB app.

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codemotion profile image
Dmitriy Belyaev

Could you describe given process to optimize NW.js package step by step?

Given article tells us about other case with 59.8Mb installer result. But you're speaking about 20Mb.

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thejaredwilcurt profile image
The Jared Wilcurt

I didn't do anything that isn't mentioned in the article. I just took it to the extreme in every scenario.

  1. The existing package.json had 4 items listed as dependencies that should have been devDependencies, so that alone shaves off like 20 MB.
  2. Built the Vue app using the Vue CLI's built in webpack commands (bundling/tree-shaking). So I'm only using the static files from the dist folder and not shipping all the source files with it. They're also minified/uglifed, but this makes very little difference.
  3. Because this app is so simple and doesn't even access Node or the OS at all. I used the older version of NW.js (0.12.3). I wouldn't normally use that version, but if filesize was my highest concern (like in this case), then I might.
  4. I removed any NW.js files that aren't needed for the app to run (this can be risky, but this is a very simple app, so I'm not worried). This takes the app down from around like 85 MB to 61.5 MB.
  5. I used WinRAR's SFX (self-extracting executable) options to create an installer. Since I'm using WinRAR to make the installer, I can take advantage of its superior compression ratio, which is what gets the 61.5 MB down to 20 MB.

In a more real world scenario the installer would be closer to 60 MB, and the installed version would be closer to 110MB. Ultimately, there is only so much you can do while shipping a copy of Node and an entire browser to your user. If filesize really is your greatest concern, then browser-based desktop apps aren't the way to go. I've compiled a list of alternative tools with pros/cons at XPDA.net

Thread Thread
willvincent profile image
Will Vincent

You could get it even smaller, probably well under 10mb with neutralino.js.org/

:)

Thread Thread
thejaredwilcurt profile image
The Jared Wilcurt

Neutralino is a neat little tool. It would certainly work in this simple app example. It has a lot of drawbacks though and you'd be better off with something more fleshed out. Even if your primary concern is filesize, there are plenty of other tools that produce very small packages with a better feature set. You can check out the cons of Neutralino, and some other alternatives here: xpda.net/#NeutralinoJs

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n_tepluhina profile image
Natalia Tepluhina Author

Thank you Jared! Would you mind if I add the link to my article too?

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thejaredwilcurt profile image
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pgangwani profile image
pgangwani

What's next step to reduce package size ?

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thejaredwilcurt profile image
The Jared Wilcurt

I'm writing up a detailed article on how to reduce the size of your NW.js app. Will post it shortly.

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n_tepluhina profile image
Natalia Tepluhina Author

Get rid of unused dependencies mostly ;)

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pgangwani profile image
pgangwani

That might not help, you have to use packager module and see. That's how all editors are packaged

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thejaredwilcurt profile image
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dekadentno profile image
Matej

Possibly a stupid question: if you wanted to store some data in the app (some database, but obviously not something like firebase, because the app shouldn't be dependable of the internet connection, right?) how would you resolve such a thing? Thanks

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n_tepluhina profile image
Natalia Tepluhina Author

There are no stupid questions ;)

You can use the database of your choice with Node.js driver, my personal choice in this case is SQLite. There is a good tutorial on how to setup SQLite with Node: stackabuse.com/a-sqlite-tutorial-w...

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dekadentno profile image
Matej

Ah yes, thanks a bunch! :)

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codemotion profile image
Dmitriy Belyaev

Have you heard that Internet Explorer is going to migrate to Chrome engine?

I wish there could be such a framework which will give us all the opportunities of Electron and NW.js but will bring it with much smaller package size. Maybe using Chrome instance of an operating system.

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n_tepluhina profile image
Natalia Tepluhina Author

Yes, I've heard about it! Still waiting for this migration.

Well, I believe JS desktop apps will have further evolution and package size reduction as well as memory usage are #1 priority. So I hope we will see this kind of framework :)

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codemotion profile image
Dmitriy Belyaev

Pay attention to GridSome — it's like Gatsby for Vue:
youtube.com/watch?v=jKmivk5bjo8

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thejaredwilcurt profile image
The Jared Wilcurt

Carlo and Lorca are attempts at this. You can read their pros/cons on XPDA.net

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edimitchel profile image
Michel EDIGHOFFER

Nice to see a different way to build native like desktop app.
But I have a question: are IE and Mozilla prefixes needed even using a Chrome browser ?

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thejaredwilcurt profile image
The Jared Wilcurt

Nope! You can set the .browserlistrc file to only support the exact version of Chromium you are using with NW.js.

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Natalia Tepluhina Author

No, I think for Chrome only you can remove them. I will remove ones from the article code snippet, thanks for spotting this! The code was from gradient generator ;)

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undavide profile image
Davide Barranca

Very nice article Natalia, thanks.

I've noticed that when the native app is pointing to localhost to get the content, the nw object (a global injected by nw.js) is undefined – you can only access when the actual build script is run. Do you have any workaround? Thanks!

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JomanWalter

This is an amazing step on how to do it. I want to start to do it right now. But very little time for everything. I would like to add a new project as soon as possible and put it on the website awards platform for compare.

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Natalia Tepluhina Author

Thank you for the comment! I am really happy you liked an article

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leshgan profile image
Leshgan

Compiled app works only when npm run serve running. How to fix that?

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n_tepluhina profile image
Natalia Tepluhina Author

You will need to take following steps:

1) add vue.config.js file with the following content:

module.exports = {
  publicPath: '.',
};

(if you use vue-cli below 3.3.0, replace publicPath with baseUrl)

2) build the project with yarn build;
3) change main in package.json to

"main": "index.html"

4) copy package.json to dist
5) run ./node_modules/.bin/build --tasks mac-x64 dist (assuming you're on OSX)

You will have your app in dist/dist folder

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mdashrafulpramanik profile image
Md-Ashraful-pramanik

This works but we can find the source file under js folder. If NW.js keep source file then why I'am use it? It will be better to use Electron. Please tell me if there is a way to build a desktop app with compiled source code from vue.

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aldisseia profile image
aldisseia

Is not working...

Add file vue.config.js in root, make command:
npm run nw-serve
compiled app works, more vue is not work

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liashchynskyi profile image
Petro Liashchynskyi

Amazing! Can we do that with React?

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Natalia Tepluhina Author

Of course! NW.js is framework-agnostic, as well as Electron, so you can use them with React.

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Dmitriy Belyaev

Natalia, thank you very much!

You're always give an inspiration for further work with your articles.

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n_tepluhina profile image
Natalia Tepluhina Author

Thank you Dmitriy! This kind of feedback definitely inspires me to continue with writing 🤗

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wenish profile image
Wenish

i guess the fallback isn't needed /* IE6-9 fallback on horizontal gradient */

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n_tepluhina profile image
Natalia Tepluhina Author

Thanks for spotting this! Will remove ;)

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aligoren profile image
Ali GOREN

Amazing article. Thanks Natalia.

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cawoodm profile image
Marc

When I run npm run nw-serve I don't get a server on 8080 - I still have to run npm run serve before npm run nw-serve. What's going wrong?

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emimassa profile image
emimassa

Do you know how to use .bin (by nwjc.exe) in a nwjs vue app?
Thank you.

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aldisseia profile image
aldisseia

npm run nw-serve
error:
Connection to localhost was declined

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angryheng profile image
angryheng

Hello, author, packing is very slow

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natonathan profile image
Nathan Tamez

Great post, just what I wanted in my next project, 😂

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downtownhub profile image
downtownhub

./node_modules/.bin/run . is error -4058
i use windows7 64bit..
what can i do???

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downtownhub profile image
downtownhub

thanks so good explain .
hi im use window7 64bit
i have error
what can i do???
i added error picture