WIP approach collecting

Author: SleeplessByte

exercises/concept/appointment-time/.approaches/config.json

@@ -0,0 +1,7 @@
+{
+  "introduction": {
+    "authors": [
+      "SleeplessByte"
+    ]
+  }
+}

exercises/concept/appointment-time/.approaches/introduction.md

@@ -0,0 +1,155 @@
+# Introduction
+
+## Default value for optional argument
+
+```javascript
+export function createAppointment(days, now = undefined) {
+  if (now === undefined) {
+    now = Date.now();
+  }
+
+  /* ... */
+}
+```
+
+```javascript
+export function createAppointment(days, now = undefined) {
+  now = now || Date.now();
+
+  /* ... */
+}
+```
+
+```javascript
+export function createAppointment(days, now = undefined) {
+  now = now ?? Date.now();
+
+  /* ... */
+}
+```
+
+```javascript
+export function createAppointment(days, now = Date.now()) {
+  /* ... */
+}
+```
+
+```javascript
+export function createAppointment(days, now = new Date()) {
+  const date = new Date(now);
+  /* ... */
+}
+```
+
+## Adding the requested days until the appointment
+
+```javascript
+date.setDate(date.getDate() + days);
+return date;
+```
+
+```javascript
+return new Date(now + days * 24 * 60 * 60 * 1000);
+```
+
+```javascript
+return new Date(now + days * 86_400_000);
+```
+
+## Generating a ISO8601 timestamp string
+
+```javascript
+return appointmentDate.toISOString();
+```
+
+```javascript
+const date_yyyy = String(appointmentDate.getUTCFullYear()).padStart(4, '0');
+const date_mm = String(appointmentDate.getUTCMonth() + 1).padStart(2, '0');
+const date_dd = String(appointmentDate.getUTCDate()).padStart(2, '0');
+
+const hh = String(appointmentDate.getUTCHours()).padStart(2, '0');
+const mm = String(appointmentDate.getUTCMinutes()).padStart(2, '0');
+const ss = String(appointmentDate.getUTCSeconds()).padStart(2, '0');
+const ms = String(appointmentDate.getUTCMilliseconds()).padStart(3, '0');
+
+return `${date_yyyy}-${date_mm}-${date_dd}T${hh}:${mm}:${ss}.${ms}Z`;
+```
+
+## Extracting the appointment details
+
+```javascript
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Named_capturing_group#browser_compatibility
+
+const regex = [
+  // matching YYYY-, extracts as year without leading zeros
+  '^(?:000(?<year>\\d{1})|00(?<year>\\d{2})|0(?<year>\\d{3})|(?<year>\\d{4}))-',
+
+  // matching MM-, extracts as month without leading zeros
+  '(?:0(?<month>\\d{1})|(?<month>\\d{2}))-',
+
+  // matching DD, extracts as date without leading zeros
+  '(?:0(?<date>\\d{1})|(?<date>\\d{2}))',
+
+  // matching T, no extraction
+  'T',
+
+  // matching HH:, extracts as hour without leading zeros
+  '(?:0(?<hour>\\d{1})|(?<hour>\\d{2})):',
+
+  // matching MM:, extracts as minute without leading zeros
+  '(?:0(?<minute>\\d{1})|(?<minute>\\d{2})):',
+
+  // matching SS:mssZ, no extraction
+  '\\d{2}\\.\\d{3}Z?$',
+].join('');
+```
+
+```javascript
+const regex = [
+  // matching YYYY-, extracts as year including leading zeros
+  '^(?<year>\\d{4})-',
+
+  // matching MM-, extracts as month without leading zeros
+  '(?<month>\\d{2})-',
+
+  // matching DD, extracts as date without leading zeros
+  '(?<date>\\d{2})',
+
+  // matching T, no extraction
+  'T',
+
+  // matching HH:, extracts as hour without leading zeros
+  '(?<hour>\\d{2}):',
+
+  // matching MM:, extracts as minute without leading zeros
+  '(?<minute>\\d{2}):',
+
+  // matching SS:mssZ, no extraction
+  '\\d{2}\\.\\d{3}Z?$',
+].join('');
+
+const detailsMatcher = new RegExp(regex);
+const match = detailsMatcher.exec(getAppointmentTimestamp(appointmentDate));
+if (!match) {
+  throw new Error('Could not extract details');
+}
+
+// TODO: roll-over minute under or overflow
+// TODO: roll-over hour under or overflow
+const details = {
+  year: match.groups ? parseInt(match.groups['year'], 10) : 0,
+  month: match.groups ? parseInt(match.groups['month'], 10) - 1 : 0,
+  date: match.groups ? parseInt(match.groups['date'], 10) : 0,
+  hour: match.groups
+    ? parseInt(match.groups['hour'], 10) -
+      appointmentDate.getTimezoneOffset() / 60
+    : 0,
+  minute: match.groups
+    ? parseInt(match.groups['minute'], 10) -
+      (appointmentDate.getTimezoneOffset() % 60)
+    : 0,
+};
+
+return details;
+``;
+```

exercises/concept/appointment-time/appointment-time.spec.js

@@ -56,6 +56,22 @@ describe('getAppointmentTimestamp', () => {
       '2000-07-16T12:00:00.000Z',
     );
   });
+
+  test('returns the correct timestamp for a very old date', () => {
+    const currentTime = new Date(Date.UTC(1600, 9, 14, 9, 1, 2, 3));
+
+    expect(getAppointmentTimestamp(currentTime)).toEqual(
+      '1600-10-14T09:01:02.003Z',
+    );
+  });
+
+  test('returns the correct timestamp for a future date', () => {
+    const currentTime = new Date(Date.UTC(3000, 0, 1, 13, 13, 13, 13));
+
+    expect(getAppointmentTimestamp(currentTime)).toEqual(
+      '3000-01-01T13:13:13.013Z',
+    );
+  });
 });
 
 describe('getAppointment', () => {