Building a simple app with Nuxt and Morris for displaying charts

This post was originally posted on Medium.

The article aims to describe (very shortly) how to create an application that will display a chart for data coming from an API.

First step, create the app with Nuxt

Nuxt is one of my favourite framework at the moment: if you are familiar with Vue.js, building an application with Nuxt is the next step to a simpler and more beautiful world 😀
So, let’s start by creating the application with the command npx create-nuxt-app

$ npx create-nuxt-app
npx : 379 installé(s) en 16.616s

> Generating Nuxt.js project in /Dev/world-bank-data
? Project name: world-bank-data
? Project description: A wonderful app with Nuxt and Morris
? Use a custom server framework: none
? Choose features to install: Axios
? Use a custom UI framework: none
? Use a custom test framework: none
? Choose rendering mode: Single Page App
? Author name: Bruno
? Choose a package manager: npm


  To get started:

        npm run dev

  To build & start for production:

        npm run build
        npm start

Important: select axios as a feature to install and choose Single Page App for the rendering mode.

Now, you can start your application with npm run dev and open http://localhost:3000. You should get something like that:

Next step, add dependencies, plugins, etc

We need two other dependencies for our application:

• vue-lodash : a library that provides utility functions (will be used to parse the result of the API
• vue-morris : a wrapper of Morris.js for Vue.js (it is a little bit old, but very efficient)

Let’s add these required dependencies :

npm i vue-lodash vue-morris --save

For a simpler use of certain dependencies, Nuxt can be enriched with plugins. Let’s do it with vue-lodash and vue-morris.

Create two files: plugins/vue-lodash.js and plugins/vue-morris.js and update nuxt.config.js to declare these plugins.

• nuxt.config.js

export default {

  /*
  ** Plugins to load before mounting the App
  */
  plugins: [
    '~/plugins/vue-lodash',
    '~/plugins/vue-morris'
  ],
}

• vue-lodash.js

import Vue from 'vue'
import VueLodash from 'vue-lodash'

// To be able to use this._ or Vue._ in the components without including lodash
Vue.use(VueLodash)

• vue-morris.js

import Raphael from 'raphael/raphael'
import jQuery from 'jquery'

// This is needed by Morris
global.Raphael = Raphael
global.jQuery = jQuery

Final step, add a new page with the chart

Now, we are going to create a page to display the 10 most populous countries in a bar chart.

The service used for this example is the API of the World Bank. They provide a lot of data, very interesting ! For more information about the API, check this page.

In our example, we use this URL: http://api.worldbank.org/v2/country/all/indicator/SP.POP.TOTL?date=2018&format=json&per_page=300&mrv=1

Parameters:

• SP.POP.TOTL: name of the indicator (in our case, the population)
• date: range of date (I just set the last year, I don’t want historical data)
• format: format of the result (it can be XML, JSON, …)
• per_page: number of result for each query (I set it to 300 to get all the results in a single query, no paging)
• mrv: fetches most recent values based on the number specified (I set it to 1, to get only the last recent value)

To query this API and get the most populous countries, the code will look like (in this method, we filter the values, sort according to the value field and keep only 10 values):

this.$axios.$get('http://api.worldbank.org/v2/country/all/indicator/SP.POP.TOTL?date=2018&format=json&per_page=300&mrv=1')
      .then(data => {
        this.countries = this._.chain(data[1])
          .filter(d => d.value && d.countryiso3code)
          .sortBy('value')
          .value()
          .slice(-10)
          .reverse()
      })

Let’s add a new file: pages/population.vue

• The <script> part: we import BarChart from vue-morris and add a mounted function that invoke the API (see above)
• The <template> part: we use the bar-chart tag for displaying the result of the call to the API.

<template>
  <section class="container">
    <h1 class="title">The 10 most populous countries</h1>
    <bar-chart id="bar" 
      :data="countries" 
      xkey="countryiso3code" 
      ykeys='["value"]' 
      labels='["Pop."]'
      resize="true" 
      bar-colors='[ "#36A2EB" ]'
      grid="true" 
      grid-text-weight="bold">
    </bar-chart>
  </section>
</template>

<script>
import { BarChart } from 'vue-morris'
export default {
  components: {
    BarChart
  },
  data() {
    return {
      countries: []
    }
  },
  mounted() {
    this.$axios.$get('http://api.worldbank.org/v2/country/all/indicator/SP.POP.TOTL?date=2018&format=json&per_page=300&mrv=1')
      .then(data => {
        this.countries = this._.chain(data[1])
          .filter(d => d.value && d.countryiso3code)
          .sortBy('value')
          .value()
          .slice(-10)
          .reverse()
      })
  }
}
</script>

Now, if you open the URL http://localhost:3000/population, you should see something like that:

Finally, we are going to create a link to navigate from the home page to the population page: update the file pages/index.vue, replace the two buttons by a <nuxt-link> (you can also remove the logo).

<template>
  ...
  <nuxt-link to="/population" class="button--grey">World population</nuxt-link>
  ...
</template>

Conclusion

As you can see, it’s very easy to create an application with Nuxt and add a simple chart framework to get rich and interactive pages.
The source code is available on github: https://github.com/bbonnin/medium-nuxt-morris. Enjoy !

Cover image by William Iven