@bytesnz

Jack Farley, Computer Engineer

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  • about
  • 6/16/2022

    JS Binary Decoder

    software

    I have recently been dealing with parsing binary data packets from various sources, and have published two NPM libraries from it - binary-decoder and sbd-direct-ip. How's how they came to be.

  • 4/19/2022

    New Zealand Low Power Wide Area Networks

    electronicssoftware

    I have started experimenting with low power wide area networks (LP-WAN) in New Zealand using a u-blox SARA-R410-02B. Here is is what I have experimented with so far.

  • 2/7/2022

    Starting with ESP32

    esp32electronicssoftwaretrap-watch

    I started developing my trap-watch project on an ESP32-CAM using the ESP IDF. Here is the newbie difficulties I ran into.

  • 2/4/2022

    VIM Window Rabbit Hole

    linux

    Developing ESP-IDF components I thought it would be great if I could make a command to open all the files for a component at once. What a rabbit hole it was. Here is how I did it.

  • 1/28/2022

    Parsing Arguments in Bash

    linux

    Making a script parse arugments in Bash took me way too long last time I did it, so here is a nice full example of how to do it using getopt

  • 1/8/2022

    Where's my bait gone?

    electronicsconservationtrap-watch

    I have recently started trapping some introduced predators around my local area and have had baits and pre-feed disappear with nothing to show for it, so I decided to get sparky and see if I could catch the culprit in the act.

  • 3/26/2021

    Bathymetric Contours

    gisgeoserveroceans

    Finally got around to creating a SLD style for GeoServer to display bathymetric contour lines using the GEBCO gridded bathymetric data. Here's how.

  • 2/25/2021

    shm That Cache

    yarndockerdevelopment

    I am often trying to find more space on my hard drives and found today my own docker containers wasting space thanks to ! Here's how I fixed it.

  • 2/2/2021

    Blob blob blob blob Stayin' Alive Stayin' Alive

    softwarejavascriptdebuggingmemory

    Upon recently trying Deezer again, I found their web app ate all my memory when running in Firefox, so I decided to see if I could find out why. I got as far as memory-file-data/string and Blobs. Here's how.

  • 12/25/2020

    A new Litter Survey

    softwarelitterlitter-survey

    In a culmination of litter surveys and litter picks, linked data and data exploration, and remoteStorage and ActivityPub, I have created a web-based litter pick/survey app that I hope will allow federated citizen science.

  • 12/13/2020

    Hoe Stream Trash

    litterpi-trash-camlitter-pick

    My latest litter pick target was Hoe Stream and the White Rose Lane Local Nature Reserve. Here's how it went.

  • 11/24/2020

    Release the Beast

    softwaregitlabcirelease

    I just created a Gitlab CI job to create a release with information from a CHANGELOG.md file for some of my projects. Here's how I did it.

  • 9/30/2020

    Gitlab CI Caching

    gitlabcontinuous integration

    I noticed something strange happening during build process during a multi-tasking bug fix. Turns out I was using Gitlab CI's caching incorrectly. I should have been using artifacts. Here's what I saw.

  • 9/21/2020

    Birthday Trash

    litterpi-trash-cam

    As a birthday treat, I took the day off work to try out my electronerised litter picker. Here's how it went.

  • 9/13/2020

    Pi Trash Cam

    raspberry pielectronicslitterpi-trash-cam

    In preparation for a day of litter picking, I finally got round to a project idea - attaching a camera to a litter picker to record it all. Here's what I did.

  • 8/25/2020

    yarn add --dev webdriverio

    first-draftsoftwaretestinggitlab

    I finally started implementing UI testing on first-draft using WebdriverIO. While writing tests was easy, getting the tests running was a little more difficult. Here is how I did it.

  • 8/16/2020

    Hooray! My new blog is live! Based on Sapper, using MongoDB and eventually ActivityPub and ActivityStreams, it will be my federated posting hub to the world.

    softwareblog
  • 8/9/2020

    Removing EXIF Data from Photos

    exifphotos

    Creating this new blog, I wanted to make sure there was no metadata data leaking personal information. Here's how I removed all the metadata tags except the ones I wanted from my photos.

  • 8/9/2020

    tmux List and Reattach

    tmuxbashsoftware

    Using tmux for your terminal multiplexer but want an easy to reattach to a session? Here's a small bash script to do it.

  • 8/8/2020

    Selectable Shell Examples

    markdownsyntaxcss

    Here's how to help your readers save time by making your post's shell commands easy to select and copy - with a simple CSS property.

  • 8/5/2020

    Be Dates You

    mongodbdocker

    Making my new blog, I didn't initially set the published dates to be native dates in the database. Here what I did to change them ...and do all the upgrades I needed.

  • 7/8/2020

    Testing vue components

    softwarevuetestingjavascript

    I recently needed to test that some Vue components were creating the correct HTML. To do this, I decided to create snapshots of Object representations of the rendered HTML.

    We recently started on building our own json-schema form generator for use in our application. We decided to go down the route of creating our own instead of using one of the various ones already available as we needed our forms to have some custom functionality, including validation warnings and extended descriptions.

    One of the things that fell on me to complete was getting the basic functionality around array types working. After reorganising the code logic to be able to work with arrays and getting the basic generation functionality working along with a storybook showing off the functionality, I decided it was about time to write some tests for the components I had created.

    Writing Tests

    Writing tests for the mixins and the utility functions was nice and simple, but writing tests to ensure that a component is spitting out what it should has always haunted me. Using jest and vue-test-utils I was able to create a wrapped shallow instance of the component under test. I then looked into ways to testing if it was what I expected, but there wasn't any great methods that I could see. Using the wrapper.html() function returned very unhelpful results (example below) that hid all the information I was wanting to check, like the values of the passed props. Digging into the vm or the vnode of the instance was just going to be too painful on some of the more complex components. So I decided to create my own utility function.

    Output of wrapper.html() function

    <container-stub formid="form-generator-2/" schema="[object Object]" config="[object Object]" fieldconfigs="[object Object]" value="hello" required="true" path=""></container-stub>

    instanceComponentObject()

    The functionality I wanted was something I have used in previous tests. In those, I called render functions with a custom createElement/h function that simply returned an Object with the tag of the component, the props passed to the component, and the children given to the component.

    result = {
      tag: 'container-stub',
      props: {
        formId: 'form-generator-2',
        schema: {
          type: 'string',
          title: 'A String'
        }
        config: {}
        fieldConfigs: {}
        value: 'hello',
        required: true,
        path: []
      },
      children: []
    }

    To do this. I ended up recursively going through the instance's vnodes and children and returning Objects to represent them. I initially did it using the vm, but found that it squashed a lot of the elements down into single children and the results were again not very handy.

    /**
     * Convert an vnode into a Object representation of it with its tag,
     * props and children
     *
     * @prop vnode VNode to convert to an Object representation
     *
     * @returns An Object representation with tag, props and children values
     */
    export const componentObject = (vnode) => {
      return (
        vnode.text || {
          tag: vnode.componentOptions?.tag || vnode.tag,
          props: vnode.data?.props,
          children:
            (vnode.children &&
              vnode.children.map((child) => componentObject(child))) ||
            []
        }
      );
    };
    
    /**
     * Convert the wrapper instance into to an Object representation of
     * the vnode including tag, props and children
     *
     * @prop instance Instance to convert
     *
     * @returns An Object representation of the vnode
     */
    export const instanceComponentObject = (instance) => {
      return instance.vnode && componentObject(instance.vnode);
    };

    (for those who haven't seen the interesting sytax before, the ?. is the new optional chaining)

    Capturing Snapshots

    Once I had the helper function in hand, I was able to easily create an instance of a component (using another helper function to create a shallow mounted instance) and compare the output of my function against the Jest snapshot

    import { shallowMount, createLocalVue } from '@vue/test-utils';
    import Vuetify from 'vuetify';
    import Vue from 'vue';
    
    import FormGenerator from '~/src/form/components/FormGenerator';
    import { instanceComponentObject, createInstance } from '~/tests/helpers/vue';
    
    Vue.use(Vuetify);
    
    /**
     * Shallow mount a component to create an instance of the component
     *
     * @prop component Component to create a shallow instance of
     * @prop props Props to pass to the component
     * @prop options Options to pass to shallowMount
     */
    const createInstance = (component, props, options) => {
      const localVue = createLocalVue();
      const vuetify = new Vuetify();
      return shallowMount(component, {
        localVue,
        vuetify,
        propsData: props || {},
        ...options
      });
    };
    
    test('it gives config, fieldConfigs, formId and require to Container', () => {
      const fieldConfigs = {
        field: {},
        'sub/field/deep': {}
      };
      const wrapper = createInstance(FormGenerator, {
        schema: {
          type: 'object',
          properties: {
            field: {},
            sub: {
              type: 'object',
              properties: {
                field: {}
              }
            }
          }
        },
        config: {
          fields: fieldConfigs
        }
      });
    
      expect(instanceComponentObject(wrapper)).toMatchSnapshot();
    });

    Pesky Asynchronous Components

    All was well after creating tests for two of the components and reviewing the created snapshots carefully to ensure they were correct. However, the third component, the container for array types, returned some strange results - everything was there except for the actual fields.

    The snapshot from before the fix without the fields

    exports[`render simple array with a current value 1`] = `
    Object {
      "children": Array [
        ...,
        Object {
          "children": Array [
            Object {
              "children": Array [
                Object {
                  "children": Array [],
                  "props": Object {
                    "icon": true,
                  },
                  "tag": "v-btn",
                },
              ],
              "props": undefined,
              "tag": "v-col-stub",
            },
          ],
          "props": undefined,
          "tag": "div",
        },
        Object {
          "children": Array [
            Object {
              "children": Array [
                Object {
                  "children": Array [],
                  "props": Object {
                    "icon": true,
                  },
                  "tag": "v-btn",
                },
              ],
              "props": undefined,
              "tag": "v-col-stub",
            },
          ],
          "props": undefined,
          "tag": "div",
        },
        ...,
      ],
      "props": undefined,
      "tag": "div",
    }  
    `;

    After a little digging, I realised that this was because the component dynamically imports a higher level container component. This is because it is the same container component that creates the array container component, so it is set as undefined in the array container. To get around this, I was able to force vue-test-utils to stub the component so that it produced the output as expected.

    The test with the forced stub.

    test('with a current value', () => {
      const wrapper = createInstance(                            
        ArrayContainer,                    
        {                  
          schema: {                                              
            type: 'array',          
            title: 'Title',
            description: 'Some description',
            items: {                                                                          
              type: 'string',
              title: 'String'
            }
          },
          formId: 'test',
          value: ['one', 'two']
        },
        {
          stubs: {
            Container: true
          }
        }
      );
    
      expect(instanceComponentObject(wrapper)).toMatchSnapshot();
    });

    The snapshot with the stub forced, now happily with the fields/container component showing.

    exports[`render simple array with a current value 1`] = `
    Object {
      "children": Array [
        ...,
        Object {
          "children": Array [
            Object {
              "children": Array [],
              "props": Object {
                "config": Object {},
                "fieldConfig": undefined,
                "fieldConfigs": undefined,
                "formId": "test",
                "path": Array [
                  0,
                ],
                "required": true,
                "schema": Object {
                  "title": "String",
                  "type": "string",
                },
                "value": "one",
              },
              "tag": "container",
            },
            Object {
              "children": Array [
                Object {
                  "children": Array [],
                  "props": Object {
                    "icon": true,
                  },
                  "tag": "v-btn",
                },
              ],
              "props": undefined,
              "tag": "v-col-stub",
            },
          ],
          "props": undefined,
          "tag": "div",
        },
        Object {
          "children": Array [
            Object {
              "children": Array [],
              "props": Object {
                "config": Object {},
                "fieldConfig": undefined,
                "fieldConfigs": undefined,
                "formId": "test",
                "path": Array [
                  1,
                ],
                "required": true,
                "schema": Object {
                  "title": "String",
                  "type": "string",
                },
                "value": "two",
              },
              "tag": "container",
            },
            Object {
              "children": Array [
                Object {
                  "children": Array [],
                  "props": Object {
                    "icon": true,
                  },
                  "tag": "v-btn",
                },
              ],
              "props": undefined,
              "tag": "v-col-stub",
            },
          ],
          "props": undefined,
          "tag": "div",
        },
        ...,
      ],
      "props": undefined,
      "tag": "div",
    }  
    `;

    Hooray.

    Close
  • 2/20/2019

    No More Numbers

    javascripthtml5software

    HTML5 number inputs aren't useful, but tel inputs, have all the power

  • 12/21/2018

    A Hacker "Hacked" Me

    securityemailgrep

    I decided to look into the extortion emails I have been getting and wrote a small script to extract the bitcoin addresses that have been used.

  • 12/7/2018

    Mouse Surgery

    pledge to not upgradeelectronics

    As part of my pledge not to upgrade, I decided to repair two of my failing mice instead of replacing them with a brand new model (as tempting as it was). Here's what I did.

  • 10/29/2018

    Danger Danger, Highly Reactive

    vuereactivegraphingdata
  • 9/11/2018

    Switching to SSR

    reactssrreact-loader
  • 8/10/2018

    Clean Docker Registry

    nodedockerconsolejavascript
  • 2/1/2018

    Testing on the Filesystem

    testingjavascript
  • 1/26/2018

    Tag You Are

    javascripttags
  • 1/25/2018

    NaN Got Me

    rubber duck savejavascriptnodejsjson
  • 4/28/2017

    All our app's tabs are belong to us

    angularjavascriptlocalstoragerxjssessionstorage
  • 2/20/2016

    Developing NPM modules

    nodejsnpm
  • 2/20/2016

    Nfa + Nfb or N(f+fa+fb)

    arrayfunctionjavascriptjsperf
  • 10/31/2015

    Photo Layout

    arrangercssgallery hierarchyhtmljavascriptphotostinymcewordpresssoftware
  • 10/31/2015

    Browning Pass HideAway Web Site

    cssgallery hierarchyhtmlwordpress
  • 10/17/2015

    Think Mobile

    mobileweb
  • 10/13/2015

    Pledge to Refuse and Not Buy Bottled Water

    environmentpledges
  • 2/25/2015

    Run PHP run!

    maximum execution timephptrial and error
  • 11/26/2014

    Gallery Hierarchy

    galleryhierarchyphotos
  • 10/3/2014

    Vim and functions

    functionnavigationtagsvim
  • 9/26/2014

    I'm making hierarchies

    hierarchical datahierarchyphp
  • 9/4/2014

    Google Sheets fun

    googlegoogle scriptgoogle sheetsjavascriptsheets
  • 8/13/2014

    Travel Photos

    photo managementphotostravel photos
  • 8/13/2014

    Image managment scripts

    photo managementphotos
  • 7/31/2014

    MeldCE logo

    csshtml5javascriptsvg
  • 4/26/2014

    MoltenDB

    databasemoltendbmongodbnodejs
  • 10/29/2013

    The Expensive Side

    house
  • 9/22/2013

    abcde

    music
  • 7/16/2013

    Energizer Power Plus Rechargeable Batteries

    gadgets
  • 3/4/2013

    USAR FOGTeX

    fogtex
  • 2/21/2013

    Personal Gear Bag

    rescuegear
  • 2/18/2013

    Geocaching Stamp

    stampgeocaching
  • 4/2/2007

    Call Record Presenter

    parserpythonsqliteweb
  • 9/25/2004

    Kimi Ora School

    csshtml
  • 6/25/2004

    All About Catering Web Site

    csshtml
  • 7/26/2003

    Quantum Accounting Web Site

    csshtml
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