Add src

src/lib/utils-habit.js

@@ -0,0 +1,42 @@
+export const formatDate = (date) => {
+  const year = date.getFullYear();
+  const month = String(date.getMonth() + 1).padStart(2, '0');
+  const day = String(date.getDate()).padStart(2, '0');
+  return `${year}-${month}-${day}`;
+};
+
+export const isToday = (date) => {
+  const today = new Date();
+  return (
+    date.getDate() === today.getDate() &&
+    date.getMonth() === today.getMonth() &&
+    date.getFullYear() === today.getFullYear()
+  );
+};
+
+export const getColorIntensity = (completions, dateStr) => {
+  const index = completions.indexOf(dateStr);
+  if (index === -1) return 0;
+
+  let streak = 1;
+  const date = new Date(dateStr);
+
+  for (let i = 1; i <= 10; i++) {
+    const prevDate = new Date(date);
+    prevDate.setDate(prevDate.getDate() - i);
+    const prevDateStr = formatDate(prevDate);
+
+    if (completions.includes(prevDateStr)) {
+      streak++;
+    } else {
+      break;
+    }
+  }
+
+  return Math.min(streak / 10, 1);
+};
+
+export const getWeekdayLabel = (dayIndex) => {
+  const labels = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'];
+  return labels[dayIndex];
+};