Showing a tree structure, like a file-system, in Vue.js

By: (plus.google.com) +David Herron; Date: July 26, 2018

Tags: Vue.js » JavaScript

Many kinds of applications show a tree structure of data items, such as files in a file system. Over the last couple weeks I implemented (blog.sourcerer.io) a simple Markdown editor in Vue.js/Electron - and while the sample application did not show a file-system tree a full version of the application would do so. We use this sort of widget all the time in programs and web applications, but do you know how to implement such a widget? Speaking for myself I could probably work it out - it's nested UL and LI elements with some custom styling and whatnot - but I'd rather use a pre-baked tree component for Vue.js instead. The application shown here demonstrates using one such tree component.

We need the Vue.js CLI tool installed. See Getting started with Vue.js application development

$ vue init webpack-simple sl-vue-tree

If you need a tour of the skeleton see Getting started with Vue.js application development

The sl-tree-vue widget is the Vue.js tree component we've chosen for this example. The code is available via npm at: (www.npmjs.com) https://www.npmjs.com/package/sl-vue-tree

To help with styling the sl-vue-tree component we'll use the Font Awesome library of icons. It is available via npm at: (www.npmjs.com) https://www.npmjs.com/package/vue-awesome

To install both:

$ cd sl-vue-tree
$ npm install sl-vue-tree vue-awesome --save
$ npm install

In index.html, make this change:

<div id="example-sl-vue-tree"></div>

In main.js use this:

import Vue from 'vue'
import App from './App.vue';

import slVueTree from 'sl-vue-tree';
import 'sl-vue-tree/dist/sl-vue-tree-dark.css';
Vue.component('sl-vue-tree', slVueTree);

import 'vue-awesome/icons';
import Icon from 'vue-awesome/components/Icon';
Vue.component('icon', Icon);

new Vue({
  el: '#example-sl-vue-tree',
  render: h => h(App)
});

The middle section is where we added code, the top and bottom is what the skeleton gave us.

The first section brings in the sl-vue-tree component. We import the component, then use Vue.component to register the component globally. We've also imported one of the theme CSS files.

The second section brings in the Font Awesome library. First we bring in the icons, then we bring in the Icon component. With that component we can use one of the icons simply with the <icon> tag.

Then, change App.vue to this:

<template>
  <div id="app">

    <sl-vue-tree v-model="nodes" @nodeclick="nodeClick">

      <template slot="toggle" slot-scope="{ node }">
          <span v-if="!node.isLeaf">
            <icon name="caret-right" v-if="!node.isExpanded"></icon>
            <icon name="caret-down"  v-if="node.isExpanded"></icon>
          </span>
      </template>

      <template slot="title" slot-scope="{ node }">
          <icon name="file" v-if="node.isLeaf"></icon> {{ node.title }} </template>

      <template slot="sidebar" slot-scope="{ node }">
          <icon name="circle" v-if="node.data.isModified"></icon>
      </template>
    </sl-vue-tree>
  </div>
</template>

<script>

var nodes = [
    {title: 'Item1', isLeaf: true},
    {title: 'Item2', isLeaf: true, data: { visible: false }},
    {title: 'Folder1'},
    {
      title: 'Folder2', isExpanded: true, children: [
        {title: 'Item3', isLeaf: true},
        {title: 'Item4', isLeaf: true, data: { isModified: true }}
      ]
    }
];

export default {
  name: 'app',
  data () {
    return {
     nodes: nodes
    }
  },
  methods: {
    nodeClick(node) {
      console.log(node);
    }
  }
}
</script>

<style>
</style>

We've set up an sl-vue-tree component, with its data stored in the nodes object. That object is fairly self-explanatory. It is an array of objects conforming to this declaration:

interface ISlTreeNodeModel<TDataType> {
    title: string;
    isLeaf?: boolean;
    children?: ISlTreeNodeModel<TDataType>[];
    isExpanded?: boolean;
    isSelected?: boolean;
    isDraggable?: boolean;
    isSelectable?: boolean;
    data?: TDataType; // any serializable user data
}

The only place you're allowed to put custom data is in the data field. In the example above we've added an isModified flag to one of items, and then in the sidebar we use that flag to show an icon.

The interesting thing about this is sl-vue-tree has several slots into which we can inject our own HTML code. In Vue.js a slot is an injectable part of the Component. Each slot is defined in the component's template, and then in the application's template we can define <template> elements that are injected into the named slot.

The toggle slot is applicable only for items with children. It shows a toggle button to control whether the children are visible. The toggle icon is only shown for non-leaf items.

The title slot renders both an icon to show the item type, as well as the name (the title field) of the item. The item type icon is only shown for leaf items.

The sidebar slot appears way over on the right side, and can be used for an extra status indicator. In this case we're planning to show a dot-thing to indicate the file is modified.

The nodeClick function is, at the moment, solely to show data about each item. Obviously it or any of the other functions supported by this component can be used for actual application-specific purposes.

Once you've made the changes, you can run it on your laptop with: npm run dev

You'll get something like this:

« Doctor Who: Silence in the Library, and Forest of the Dead What is Shadow Banning? Banning a member such that they do not know they're banned »
2016 Election Acer C720 Ad block AkashaCMS Amazon Amazon Kindle Amazon Web Services America Amiga and Jon Pertwee Android Anti-Fascism AntiVirus Software Apple Apple Hardware History Apple iPhone Apple iPhone Hardware April 1st Arduino ARM Compilation Artificial Intelligence Astronomy Astrophotography Asynchronous Programming Authoritarianism Automated Social Posting AWS DynamoDB AWS Lambda Ayo.JS Bells Law Big Brother Big Finish Bitcoin Mining Black Holes Blade Runner Blockchain Blogger Blogging Books Botnets Cassette Tapes Cellphones China China Manufacturing Christopher Eccleston Chrome Chrome Apps Chromebook Chromebox ChromeOS CIA CitiCards Citizen Journalism Civil Liberties Clinton Cluster Computing Command Line Tools Comment Systems Computer Accessories Computer Hardware Computer Repair Computers Cross Compilation Crouton Cryptocurrency Curiosity Rover Currencies Cyber Security Cybermen Daleks Darth Vader Data backup Data Storage Database Database Backup Databases David Tenant DDoS Botnet Detect Adblocker Developers Editors Digital Photography Diskless Booting Disqus DIY DIY Repair DNP3 Do it yourself Docker Docker MAMP Docker Swarm Doctor Who Doctor Who Paradox Doctor Who Review Drobo Drupal Drupal Themes DVD E-Books E-Readers Early Computers Election Hacks Electric Bicycles Electric Vehicles Electron Emdebian Encabulators Energy Efficiency Enterprise Node EPUB ESP8266 Ethical Curation Eurovision Event Driven Asynchronous Express Face Recognition Facebook Fake News Fedora VirtualBox File transfer without iTunes FireFly Flickr Fraud Freedom of Speech Front-end Development Gallifrey git Github GitKraken Gitlab GMAIL Google Google Chrome Google Gnome Google+ Government Spying Great Britain Heat Loss Hibernate Hoax Science Home Automation HTTP Security HTTPS Human ID I2C Protocol Image Analysis Image Conversion Image Processing ImageMagick In-memory Computing InfluxDB Infrared Thermometers Insulation Internet Internet Advertising Internet Law Internet of Things Internet Policy Internet Privacy iOS Devices iPad iPhone iPhone hacking Iron Man iTunes Java JavaScript JavaScript Injection JDBC John Simms Journalism Joyent Kaspersky Labs Kindle Kindle Marketplace Lets Encrypt LibreOffice Linux Linux Hints Linux Single Board Computers Logging Mac Mini Mac OS Mac OS X Machine Learning Machine Readable ID macOS MacOS X setup Make Money Online March For Our Lives MariaDB Mars Mass Violence Matt Lucas MEADS Anti-Missile Mercurial MERN Stack Michele Gomez Micro Apartments Microsoft Military AI Military Hardware Minification Minimized CSS Minimized HTML Minimized JavaScript Missy Mobile Applications Mobile Computers MODBUS Mondas Monetary System MongoDB Mongoose Monty Python MQTT Music Player Music Streaming MySQL NanoPi Nardole NASA Net Neutrality Network Attached Storage Node Web Development Node.js Node.js Database Node.js Testing Node.JS Web Development Node.x North Korea npm NVIDIA NY Times Online advertising Online Community Online Fraud Online Journalism Online Photography Online Video Open Media Vault Open Source Open Source Governance Open Source Licenses Open Source Software OpenAPI OpenVPN Palmtop PDA Patrick Troughton Paywalls Personal Flight Peter Capaldi Phishing Photography PHP Plex Plex Media Server Political Protest Postal Service Power Control Privacy Production use Public Violence Raspberry Pi Raspberry Pi 3 Raspberry Pi Zero ReactJS Recaptcha Recycling Refurbished Computers Remote Desktop Removable Storage Republicans Retro Computing Retro-Technology Reviews RFID Right to Repair River Song Robotics Rocket Ships RSS News Readers rsync Russia Russia Troll Factory Russian Hacking Rust SCADA Scheme Science Fiction SD Cards Search Engine Ranking Season 1 Season 10 Season 11 Security Security Cameras Server-side JavaScript Serverless Framework Servers Shell Scripts Silence Simsimi Skype SmugMug Social Media Social Media Warfare Social Network Management Social Networks Software Development Space Flight Space Ship Reuse Space Ships SpaceX Spear Phishing Spring Spring Boot Spy Satellites SQLite3 SSD Drives SSD upgrade SSH SSH Key SSL Stand For Truth Strange Parts Swagger Synchronizing Files Telescopes Terrorism The Cybermen The Daleks The Master Time-Series Database Tom Baker Torchwood Total Information Awareness Trump Trump Administration Trump Campaign Twitter Ubuntu Udemy UDOO US Department of Defense Virtual Private Networks VirtualBox VLC VNC VOIP Vue.js Web Applications Web Developer Resources Web Development Web Development Tools Web Marketing Webpack Website Advertising Weeping Angels WhatsApp William Hartnell Window Insulation Windows Windows Alternatives Wordpress World Wide Web Yahoo YouTube YouTube Monetization