diff --git a/assets/js/__tests__/search.spec.ts b/assets/js/__tests__/search.spec.ts
new file mode 100644
index 00000000..abc033b5
--- /dev/null
+++ b/assets/js/__tests__/search.spec.ts
@@ -0,0 +1,99 @@
+import { $ } from '../utils/dom';
+import { assertNotNull } from '../utils/assert';
+import { setupSearch } from '../search';
+import { setupTagListener } from '../tagsinput';
+
+const formData = `<form class="js-search-form">
+  <input type="text" class="js-search-field">
+  <a data-search-prepend="-">NOT</a>
+  <a data-search-add="id.lte:10" data-search-select-last="2" data-search-show-help="numeric">Numeric ID</a>
+  <a data-search-add="my:faves" data-search-show-help=" ">My favorites</a>
+  <div class="hidden" data-search-help="boolean">
+    <span class="js-search-help-subject"></span> is a Boolean value field
+  </div>
+  <div class="hidden" data-search-help="numeric">
+    <span class="js-search-help-subject"></span> is a numerical range field
+  </div>
+</form>`;
+
+describe('Search form help', () => {
+  beforeAll(() => {
+    setupSearch();
+    setupTagListener();
+  });
+
+  let input: HTMLInputElement;
+  let prependAnchor: HTMLAnchorElement;
+  let idAnchor: HTMLAnchorElement;
+  let favesAnchor: HTMLAnchorElement;
+  let helpNumeric: HTMLDivElement;
+  let subjectSpan: HTMLElement;
+
+  beforeEach(() => {
+    document.body.innerHTML = formData;
+
+    input = assertNotNull($<HTMLInputElement>('input'));
+    prependAnchor = assertNotNull($<HTMLAnchorElement>('a[data-search-prepend]'));
+    idAnchor = assertNotNull($<HTMLAnchorElement>('a[data-search-add="id.lte:10"]'));
+    favesAnchor = assertNotNull($<HTMLAnchorElement>('a[data-search-add="my:faves"]'));
+    helpNumeric = assertNotNull($<HTMLDivElement>('[data-search-help="numeric"]'));
+    subjectSpan = assertNotNull($<HTMLSpanElement>('span', helpNumeric));
+  });
+
+  it('should add text to input field', () => {
+    idAnchor.click();
+    expect(input.value).toBe('id.lte:10');
+
+    favesAnchor.click();
+    expect(input.value).toBe('id.lte:10, my:faves');
+  });
+
+  it('should focus and select text in input field when requested', () => {
+    idAnchor.click();
+    expect(input).toHaveFocus();
+    expect(input.selectionStart).toBe(7);
+    expect(input.selectionEnd).toBe(9);
+  });
+
+  it('should highlight subject name when requested', () => {
+    expect(helpNumeric).toHaveClass('hidden');
+    idAnchor.click();
+    expect(helpNumeric).not.toHaveClass('hidden');
+    expect(subjectSpan).toHaveTextContent('Numeric ID');
+  });
+
+  it('should not focus and select text in input field when unavailable', () => {
+    favesAnchor.click();
+    expect(input).not.toHaveFocus();
+    expect(input.selectionStart).toBe(8);
+    expect(input.selectionEnd).toBe(8);
+  });
+
+  it('should not highlight subject name when unavailable', () => {
+    favesAnchor.click();
+    expect(helpNumeric).toHaveClass('hidden');
+  });
+
+  it('should prepend to empty input', () => {
+    prependAnchor.click();
+    expect(input.value).toBe('-');
+  });
+
+  it('should prepend to single input', () => {
+    input.value = 'a';
+    prependAnchor.click();
+    expect(input.value).toBe('-a');
+  });
+
+  it('should prepend to comma-separated input', () => {
+    input.value = 'a,b';
+    prependAnchor.click();
+    expect(input.value).toBe('a,-b');
+  });
+
+  it('should prepend to comma and space-separated input', () => {
+    input.value = 'a, b';
+    prependAnchor.click();
+    expect(input.value).toBe('a, -b');
+  });
+});
diff --git a/assets/js/search.js b/assets/js/search.js
deleted file mode 100644
index 50733fd9..00000000
--- a/assets/js/search.js
+++ /dev/null
@@ -1,45 +0,0 @@
-import { $, $$ } from './utils/dom';
-import { addTag } from './tagsinput';
-
-function showHelp(subject, type) {
-  $$('[data-search-help]').forEach(helpBox => {
-    if (helpBox.getAttribute('data-search-help') === type) {
-      $('.js-search-help-subject', helpBox).textContent = subject;
-      helpBox.classList.remove('hidden');
-    } else {
-      helpBox.classList.add('hidden');
-    }
-  });
-}
-
-function prependToLast(field, value) {
-  const separatorIndex = field.value.lastIndexOf(',');
-  const advanceBy = field.value[separatorIndex + 1] === ' ' ? 2 : 1;
-  field.value =
-    field.value.slice(0, separatorIndex + advanceBy) + value + field.value.slice(separatorIndex + advanceBy);
-}
-
-function selectLast(field, characterCount) {
-  field.focus();
-
-  field.selectionStart = field.value.length - characterCount;
-  field.selectionEnd = field.value.length;
-}
-
-function executeFormHelper(e) {
-  const searchField = $('.js-search-field');
-  const attr = name => e.target.getAttribute(name);
-
-  attr('data-search-add') && addTag(searchField, attr('data-search-add'));
-  attr('data-search-show-help') && showHelp(e.target.textContent, attr('data-search-show-help'));
-  attr('data-search-select-last') && selectLast(searchField, parseInt(attr('data-search-select-last'), 10));
-  attr('data-search-prepend') && prependToLast(searchField, attr('data-search-prepend'));
-}
-
-function setupSearch() {
-  const form = $('.js-search-form');
-
-  form && form.addEventListener('click', executeFormHelper);
-}
-
-export { setupSearch };
diff --git a/assets/js/search.ts b/assets/js/search.ts
new file mode 100644
index 00000000..eff8d98a
--- /dev/null
+++ b/assets/js/search.ts
@@ -0,0 +1,85 @@
+import { assertNotNull, assertNotUndefined } from './utils/assert';
+import { $, $$, showEl, hideEl } from './utils/dom';
+import { delegate, leftClick } from './utils/events';
+import { addTag } from './tagsinput';
+
+function focusAndSelectLast(field: HTMLInputElement, characterCount: number) {
+  field.focus();
+  field.selectionStart = field.value.length - characterCount;
+  field.selectionEnd = field.value.length;
+}
+
+function prependToLast(field: HTMLInputElement, value: string) {
+  // Find the last comma in the input and advance past it
+  const separatorIndex = field.value.lastIndexOf(',');
+  const advanceBy = field.value[separatorIndex + 1] === ' ' ? 2 : 1;
+
+  // Insert the value string at the new location
+  field.value = [
+    field.value.slice(0, separatorIndex + advanceBy),
+    value,
+    field.value.slice(separatorIndex + advanceBy),
+  ].join('');
+}
+
+function getAssociatedData(target: HTMLElement) {
+  const form = assertNotNull(target.closest('form'));
+  const input = assertNotNull($<HTMLInputElement>('.js-search-field', form));
+  const helpBoxes = $$<HTMLDivElement>('[data-search-help]', form);
+
+  return { input, helpBoxes };
+}
+
+function showHelp(helpBoxes: HTMLDivElement[], typeName: string, subject: string) {
+  for (const helpBox of helpBoxes) {
+    // Get the subject name span
+    const subjectName = assertNotNull($<HTMLElement>('.js-search-help-subject', helpBox));
+
+    // Take the appropriate action for this help box
+    if (helpBox.dataset.searchHelp === typeName) {
+      subjectName.textContent = subject;
+      showEl(helpBox);
+    } else {
+      hideEl(helpBox);
+    }
+  }
+}
+
+function onSearchAdd(_event: Event, target: HTMLAnchorElement) {
+  // Load form
+  const { input, helpBoxes } = getAssociatedData(target);
+
+  // Get data for this link
+  const addValue = assertNotUndefined(target.dataset.searchAdd);
+  const showHelpValue = assertNotUndefined(target.dataset.searchShowHelp);
+  const selectLastValue = target.dataset.searchSelectLast;
+
+  // Add the tag
+  addTag(input, addValue);
+
+  // Show associated help, if available
+  showHelp(helpBoxes, showHelpValue, assertNotNull(target.textContent));
+
+  // Select last characters, if requested
+  if (selectLastValue) {
+    focusAndSelectLast(input, Number(selectLastValue));
+  }
+}
+
+function onSearchPrepend(_event: Event, target: HTMLAnchorElement) {
+  // Load form
+  const { input } = getAssociatedData(target);
+
+  // Get data for this link
+  const prependValue = assertNotUndefined(target.dataset.searchPrepend);
+
+  // Prepend
+  prependToLast(input, prependValue);
+}
+
+export function setupSearch() {
+  delegate(document, 'click', {
+    'form.js-search-form a[data-search-add][data-search-show-help]': leftClick(onSearchAdd),
+    'form.js-search-form a[data-search-prepend]': leftClick(onSearchPrepend),
+  });
+}