[#146] feat: 시간 경과 계산 함수 생성

Author: YiSoJeong

frontend/src/utils/index.ts

@@ -1,11 +1,7 @@
 export { fetchDummyData } from './fetchDummyData';
-export {
-  validateType,
-  fontSize,
-  placeHolder,
-  listComponent,
-} from './blockContent';
+export * from './blockContent';
 export * from './debounce';
 export * from './fetchApi';
 export * from './blockApis';
 export * from './pageApis';
+export * from './time';

frontend/src/utils/time.ts

@@ -0,0 +1,26 @@
+export const timeSince = (date: Date) => {
+  const seconds = Math.floor((+new Date() - +date) / 1000);
+
+  let interval = seconds / 31536000;
+
+  if (interval > 1) {
+    return `${Math.floor(interval)} years`;
+  }
+  interval = seconds / 2592000;
+  if (interval > 1) {
+    return `${Math.floor(interval)} months`;
+  }
+  interval = seconds / 86400;
+  if (interval > 1) {
+    return `${Math.floor(interval)} days`;
+  }
+  interval = seconds / 3600;
+  if (interval > 1) {
+    return `${Math.floor(interval)} hours`;
+  }
+  interval = seconds / 60;
+  if (interval > 1) {
+    return `${Math.floor(interval)} minutes`;
+  }
+  return `${Math.floor(seconds)} seconds`;
+};