Improve budget joining view and add screen reader compatibility

frontend/src/components/budget-join.ts

@@ -1,12 +1,15 @@
 import { LitElement, html } from 'lit-element'
-import { InputField } from './input';
-import { QRReadEvent } from './budget-qr-reader';
+import { InputField } from './input'
+import './budget-qr-reader'
+import { QRReadEvent } from './budget-qr-reader'
+import { ERROR_TIMER } from '../config'
 
 export class JoinBudgetEvent extends CustomEvent<{ uuid: string }> { }
 
 class BudgetJoinComponent extends LitElement {
   hasError: boolean = false
   showQRReader: boolean = false
+  errorTimer: number = null
 
   static get properties() {
     return {
@@ -15,9 +18,30 @@ class BudgetJoinComponent extends LitElement {
     }
   }
 
+  firstUpdated() {
+    const secretInputEl = <InputField>this.shadowRoot.getElementById('uuid')
+    secretInputEl.focusInput()
+  }
+
+  updated(changedProperties: Map<string | number | symbol, any>) {
+    // If error was turned on, turn it off after a moment
+    if (changedProperties.has('hasError')) {
+      if (this.errorTimer != null) {
+        window.clearTimeout(this.errorTimer)
+      }
+
+      this.errorTimer = window.setTimeout(() => {
+        this.hasError = false
+        this.errorTimer = null
+      }, ERROR_TIMER * 1000)
+    }
+
+    return super.updated(changedProperties)
+  }
+
   onJoin(e: Event) {
     e.preventDefault()
-    const inputEl = <InputField>this.shadowRoot.getElementById('join-budget-uuid')
+    const inputEl = <InputField>this.shadowRoot.getElementById('uuid')
 
     this.dispatchEvent(new JoinBudgetEvent(
       'joinBudget',
@@ -42,12 +66,10 @@ class BudgetJoinComponent extends LitElement {
 
   render() {
     return html`
-      <p>Add below the budget secret that you can get from the person who created the budget.</p>
       <input-field
-        id="join-budget-uuid"
+        id="uuid"
         type="text"
-        label="Budget secret"
-        placeholder="aaaaaaaa-bbbb-4ccc-9ddd-ffffffffffff"
+        label="Budget secret (ask someone to share theirs)"
         maxlength="36"
         pattern="[0-9A-Fa-f]{8}-[0-9A-Fa-f]{4}-4[0-9A-Fa-f]{3}-[89ABab][0-9A-Fa-f]{3}-[0-9A-Fa-f]{12}"
         required
@@ -56,14 +78,17 @@ class BudgetJoinComponent extends LitElement {
         <fa-icon name="plus" alt="Join budget"></fa-icon>
       </fa-button>
       <fa-button type="button" @click=${this.toggleShowQRReader}>
-        <fa-icon name="qrcode" alt="Read QR using camera"></fa-icon>
+        <fa-icon
+          name="qrcode"
+          alt="${(!this.showQRReader) ? 'Read QR using camera' : 'Stop reading QR'}"
+        ></fa-icon>
       </fa-button>
 
       <div>
         ${this.showQRReader ? html`<budget-qr-reader @qrRead=${this.onQRRead}></budget-qr-reader>` : null}
       </div>
 
-      ${this.hasError ? html`<p>Could not add given budget, please check it is correctly typed.</p>` : null}
+      ${this.hasError ? html`<p role="alert">Could not add given budget, please check it is correctly typed.</p>` : null}
     `
   }
 }

frontend/src/components/budget-qr-reader.ts

@@ -1,5 +1,6 @@
-import { LitElement, html } from 'lit-element'
+import { LitElement, html, css } from 'lit-element'
 import { BrowserQRCodeReader, VideoInputDevice } from '../vendor/zxing-typescript/src/browser/BrowserQRCodeReader'
+import { SR_ONLY } from './styles'
 
 export class QRReadEvent extends CustomEvent<{ text: string }> { }
 
@@ -9,16 +10,26 @@ class BudgetQRReaderComponent extends LitElement {
   reader: BrowserQRCodeReader
   inputs: VideoInputDevice[]
   currentInput: string
+  currentInputLabel: string
   test: string
+  scanActive: boolean
 
   static get properties() {
     return {
       inputs: { type: Array },
       currentInput: { type: String },
-      test: { type: String }
+      currentInputLabel: { type: String },
+      test: { type: String },
+      scanActive: { type: Boolean }
     }
   }
 
+  static get styles() {
+    return css`
+      ${SR_ONLY}
+    `
+  }
+
   constructor() {
     super()
 
@@ -31,6 +42,7 @@ class BudgetQRReaderComponent extends LitElement {
     this.inputs = await this.reader.getVideoInputDevices()
     if (this.inputs.length > 0) {
       this.currentInput = this.inputs[0].deviceId
+      this.currentInputLabel = this.inputs[0].label
       this.startRead()
     }
   }
@@ -54,6 +66,7 @@ class BudgetQRReaderComponent extends LitElement {
 
     let found = false
     do {
+      this.scanActive = true
       const result = await this.reader.decodeFromInputVideoDevice(this.currentInput, videoEl)
       const text = result.getText()
       if (this._isUUID(text)) {
@@ -67,13 +80,23 @@ class BudgetQRReaderComponent extends LitElement {
   }
 
   stopRead() {
+    this.scanActive = false
     this.reader.reset()
   }
 
+  inputChanged() {
+    const inputEl = <HTMLSelectElement>this.shadowRoot.getElementById('input')
+    this.currentInput = inputEl.value
+    this.currentInputLabel = inputEl.options[inputEl.selectedIndex].label
+    this.stopRead()
+    this.startRead()
+  }
+
   render() {
     return html`
+      ${this.scanActive ? html`<p role="alert" class="sr-only">Now scanning for QR codes with device ${this.currentInputLabel}.</p>` : null}
       <video id="video" width="300" height="200" style="border: 1px solid gray"></video>
-      <select id="qr-reader-input">
+      <select id="input" @change="${this.inputChanged}">
         ${this.inputs.map(input => this.renderVideoInput(input))}
       </select>
     `

frontend/src/components/icon.ts

@@ -1,4 +1,5 @@
 import { LitElement, html, css, unsafeCSS } from 'lit-element'
+import { SR_ONLY } from './styles'
 
 /**
  * An accessible Font Awesome icon. Normally FA icons are not read by screen readers, leading to bad
@@ -54,17 +55,7 @@ function icon2css(name: string, code: string) {
 }
 
 const FA_CSS = css`
-  /* From https://webaim.org/techniques/css/invisiblecontent/ */
-  .sr-only {
-    clip: rect(1px, 1px, 1px, 1px);
-    clip-path: inset(50%);
-    height: 1px;
-    width: 1px;
-    margin: -1px;
-    overflow: hidden;
-    padding: 0;
-    position: absolute;
-  }
+  ${SR_ONLY}
 
   .fa,
   .fas,

frontend/src/components/styles.ts

@@ -4,3 +4,18 @@ import { css } from 'lit-element'
  * Breakpoint media query to use for mobile layouts.
  */
 export const MOB_BP = css`@media (max-width: 768px)`
+
+/** Show something only for screen readers. */
+export const SR_ONLY = css`
+  /* From https://webaim.org/techniques/css/invisiblecontent/ */
+  .sr-only {
+    clip: rect(1px, 1px, 1px, 1px);
+    clip-path: inset(50%);
+    height: 1px;
+    width: 1px;
+    margin: -1px;
+    overflow: hidden;
+    padding: 0;
+    position: absolute;
+  }
+`