Add accessible autocomplete improvements (#728)

* Add accessible autocomplete improvements

* lint

* Add a check for matches

app/frontend/controllers/accessible_autocomplete_controller.js

@@ -1,12 +1,36 @@
 import { Controller } from '@hotwired/stimulus'
 import accessibleAutocomplete from 'accessible-autocomplete'
 import 'accessible-autocomplete/dist/accessible-autocomplete.min.css'
+import { enhanceOption, suggestion, sort } from '../modules/search'
 
 export default class extends Controller {
   connect () {
+    const selectEl = this.element
+    const selectOptions = Array.from(selectEl.options)
+    const options = selectOptions.map((o) => enhanceOption(o))
+
+    const matches = /^(\w+)\[(\w+)\]$/.exec(selectEl.name)
+    const rawFieldName = matches ? `${matches[1]}[${matches[2]}_raw]` : ''
+
     accessibleAutocomplete.enhanceSelectElement({
       defaultValue: '',
-      selectElement: this.element
+      selectElement: selectEl,
+      minLength: 2,
+      source: (query, populateResults) => {
+        if (/\S/.test(query)) {
+          populateResults(sort(query, options))
+        }
+      },
+      autoselect: true,
+      templates: { suggestion: (value) => suggestion(value, options) },
+      name: rawFieldName,
+      onConfirm: (val) => {
+        const selectedOption = [].filter.call(
+          selectOptions,
+          (option) => (option.textContent || option.innerText) === val
+        )[0]
+        if (selectedOption) selectedOption.selected = true
+      }
     })
   }
 }

app/frontend/modules/search.js

@@ -0,0 +1,106 @@
+const addWeightWithBoost = (option, query) => {
+  option.weight = calculateWeight(option.clean, query) * option.clean.boost
+
+  return option
+}
+
+const clean = (text) =>
+  text
+    .trim()
+    .replace(/['’]/g, '')
+    .replace(/[.,"/#!$%^&*;:{}=\-_`~()]/g, ' ')
+    .toLowerCase()
+
+const cleanseOption = (option) => {
+  option.clean = {
+    name: clean(option.name),
+    nameWithoutStopWords: removeStopWords(option.name),
+    boost: option.boost || 1
+  }
+
+  return option
+}
+
+const hasWeight = (option) => option.weight > 0
+
+const byWeightThenAlphabetically = (a, b) => {
+  if (a.weight > b.weight) return -1
+  if (a.weight < b.weight) return 1
+  if (a.name < b.name) return -1
+  if (a.name > b.name) return 1
+
+  return 0
+}
+
+const optionName = (option) => option.name
+const exactMatch = (word, query) => word === query
+
+const startsWithRegExp = (query) => new RegExp('\\b' + query, 'i')
+const startsWith = (word, query) => word.search(startsWithRegExp(query)) === 0
+
+const wordsStartsWithQuery = (word, regExps) =>
+  regExps.every((regExp) => word.search(regExp) >= 0)
+
+const calculateWeight = ({ name, nameWithoutStopWords }, query) => {
+  const queryWithoutStopWords = removeStopWords(query)
+
+  if (exactMatch(name, query)) return 100
+  if (exactMatch(nameWithoutStopWords, queryWithoutStopWords)) return 95
+
+  if (startsWith(name, query)) return 60
+  if (startsWith(nameWithoutStopWords, queryWithoutStopWords)) return 55
+  const startsWithRegExps = queryWithoutStopWords
+    .split(/\s+/)
+    .map(startsWithRegExp)
+
+  if (wordsStartsWithQuery(nameWithoutStopWords, startsWithRegExps)) return 25
+
+  return 0
+}
+
+const stopWords = ['the', 'of', 'in', 'and', 'at', '&']
+
+const removeStopWords = (text) => {
+  const isAllStopWords = text
+    .trim()
+    .split(' ')
+    .every((word) => stopWords.includes(word))
+
+  if (isAllStopWords) {
+    return text
+  }
+
+  const regex = new RegExp(
+    stopWords.map((word) => `(\\s+)?${word}(\\s+)?`).join('|'),
+    'gi'
+  )
+  return text.replace(regex, ' ').trim()
+}
+
+export const sort = (query, options) => {
+  const cleanQuery = clean(query)
+
+  return options
+    .map(cleanseOption)
+    .map((option) => addWeightWithBoost(option, cleanQuery))
+    .filter(hasWeight)
+    .sort(byWeightThenAlphabetically)
+    .map(optionName)
+}
+
+export const suggestion = (value, options) => {
+  const option = options.find((o) => o.name === value)
+  if (option) {
+    const html = `<span>${value}</span>`
+    return html
+  } else {
+    return '<span>No results found</span>'
+  }
+}
+
+export const enhanceOption = (option) => {
+  return {
+    name: option.label,
+    boost: parseFloat(option.getAttribute('data-boost')) || 1
+  }
+}

spec/features/form/accessible_autocomplete_spec.rb

@@ -21,14 +21,32 @@ RSpec.describe "Accessible Automcomplete" do
     sign_in user
   end
 
-  it "allows type ahead filtering", js: true do
+  context "when using accessible autocomplete" do
+    before do
       visit("/logs/#{case_log.id}/accessible-select")
+    end
+
+    it "allows type ahead filtering", js: true do
       find("#case-log-prevloc-field").click.native.send_keys("T", "h", "a", "n", :down, :enter)
       expect(find("#case-log-prevloc-field").value).to eq("Thanet")
     end
 
+    it "ignores punctuation", js: true do
+      find("#case-log-prevloc-field").click.native.send_keys("T", "h", "a", "'", "n", :down, :enter)
+      expect(find("#case-log-prevloc-field").value).to eq("Thanet")
+    end
+
+    it "ignores stop words", js: true do
+      find("#case-log-prevloc-field").click.native.send_keys("t", "h", "e", " ", "W", "e", "s", "t", "m", :down, :enter)
+      expect(find("#case-log-prevloc-field").value).to eq("Westminster")
+    end
+
+    it "does not perform an exact match", js: true do
+      find("#case-log-prevloc-field").click.native.send_keys("o", "n", "l", "y", " ", "t", "o", "w", "n", :down, :enter)
+      expect(find("#case-log-prevloc-field").value).to eq("The one and only york town")
+    end
+
     it "maintains enhancement state across back navigation", js: true do
-    visit("/logs/#{case_log.id}/accessible-select")
       find("#case-log-prevloc-field").click.native.send_keys("T", "h", "a", "n", :down, :enter)
       click_button("Save and continue")
       click_link(text: "Back")
@@ -36,9 +54,9 @@ RSpec.describe "Accessible Automcomplete" do
     end
 
     it "has a disabled null option" do
-    visit("/logs/#{case_log.id}/accessible-select")
       expect(page).to have_select("case-log-prevloc-field", disabled_options: ["Select an option"])
     end
+  end
 
   it "has the correct option selected if one has been saved" do
     case_log.update!(postcode_known: 0, previous_la_known: 1, prevloc: "E07000178")

spec/fixtures/forms/2021_2022.json

@@ -326,7 +326,7 @@
                       "E07000178": "Oxford",
                       "E07000114": "Thanet",
                       "E09000033": "Westminster",
-                      "E06000014": "York"
+                      "E06000014": "The one and only york town"
                     }
                   }
                 },

spec/models/form/question_spec.rb

@@ -158,7 +158,7 @@ RSpec.describe Form::Question, type: :model do
     end
 
     it "can map label from value" do
-      expect(question.label_from_value("E06000014")).to eq("York")
+      expect(question.label_from_value("E09000033")).to eq("Westminster")
     end
 
     context "when the saved answer is not in the value map" do