feat(std/datetime): generalise parser, add formatter (#6619)

1 files changed, 12 insertions, 78 deletions

diff --git a/std/datetime/mod.ts b/std/datetime/mod.ts
index fe6fe6b3c..e47fe9e01 100644
--- a/std/datetime/mod.ts
+++ b/std/datetime/mod.ts
@@ -1,7 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-import { assert } from "../_util/assert.ts";
 
-export type DateFormat = "mm-dd-yyyy" | "dd-mm-yyyy" | "yyyy-mm-dd";
+import { DateTimeFormatter } from "./formatter.ts";
 
 export const SECOND = 1e3;
 export const MINUTE = SECOND * 60;
@@ -20,92 +19,27 @@ enum Day {
   Sat,
 }
 
-function execForce(reg: RegExp, pat: string): RegExpExecArray {
-  const v = reg.exec(pat);
-  assert(v != null);
-  return v;
-}
 /**
  * Parse date from string using format string
- * @param dateStr Date string
+ * @param dateString Date string
  * @param format Format string
  * @return Parsed date
  */
-export function parseDate(dateStr: string, format: DateFormat): Date {
-  let m, d, y: string;
-  let datePattern: RegExp;
-
-  switch (format) {
-    case "mm-dd-yyyy":
-      datePattern = /^(\d{2})-(\d{2})-(\d{4})$/;
-      [, m, d, y] = execForce(datePattern, dateStr);
-      break;
-    case "dd-mm-yyyy":
-      datePattern = /^(\d{2})-(\d{2})-(\d{4})$/;
-      [, d, m, y] = execForce(datePattern, dateStr);
-      break;
-    case "yyyy-mm-dd":
-      datePattern = /^(\d{4})-(\d{2})-(\d{2})$/;
-      [, y, m, d] = execForce(datePattern, dateStr);
-      break;
-    default:
-      throw new Error("Invalid date format!");
-  }
-
-  return new Date(Number(y), Number(m) - 1, Number(d));
+export function parse(dateString: string, formatString: string): Date {
+  const formatter = new DateTimeFormatter(formatString);
+  const parts = formatter.parseToParts(dateString);
+  return formatter.partsToDate(parts);
 }
 
-export type DateTimeFormat =
-  | "mm-dd-yyyy hh:mm"
-  | "dd-mm-yyyy hh:mm"
-  | "yyyy-mm-dd hh:mm"
-  | "hh:mm mm-dd-yyyy"
-  | "hh:mm dd-mm-yyyy"
-  | "hh:mm yyyy-mm-dd";
-
 /**
- * Parse date & time from string using format string
- * @param dateStr Date & time string
+ * Format date using format string
+ * @param date Date
  * @param format Format string
- * @return Parsed date
+ * @return formatted date string
  */
-export function parseDateTime(
-  datetimeStr: string,
-  format: DateTimeFormat,
-): Date {
-  let m, d, y, ho, mi: string;
-  let datePattern: RegExp;
-
-  switch (format) {
-    case "mm-dd-yyyy hh:mm":
-      datePattern = /^(\d{2})-(\d{2})-(\d{4}) (\d{2}):(\d{2})$/;
-      [, m, d, y, ho, mi] = execForce(datePattern, datetimeStr);
-      break;
-    case "dd-mm-yyyy hh:mm":
-      datePattern = /^(\d{2})-(\d{2})-(\d{4}) (\d{2}):(\d{2})$/;
-      [, d, m, y, ho, mi] = execForce(datePattern, datetimeStr);
-      break;
-    case "yyyy-mm-dd hh:mm":
-      datePattern = /^(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2})$/;
-      [, y, m, d, ho, mi] = execForce(datePattern, datetimeStr);
-      break;
-    case "hh:mm mm-dd-yyyy":
-      datePattern = /^(\d{2}):(\d{2}) (\d{2})-(\d{2})-(\d{4})$/;
-      [, ho, mi, m, d, y] = execForce(datePattern, datetimeStr);
-      break;
-    case "hh:mm dd-mm-yyyy":
-      datePattern = /^(\d{2}):(\d{2}) (\d{2})-(\d{2})-(\d{4})$/;
-      [, ho, mi, d, m, y] = execForce(datePattern, datetimeStr);
-      break;
-    case "hh:mm yyyy-mm-dd":
-      datePattern = /^(\d{2}):(\d{2}) (\d{4})-(\d{2})-(\d{2})$/;
-      [, ho, mi, y, m, d] = execForce(datePattern, datetimeStr);
-      break;
-    default:
-      throw new Error("Invalid datetime format!");
-  }
-
-  return new Date(Number(y), Number(m) - 1, Number(d), Number(ho), Number(mi));
+export function format(date: Date, formatString: string): string {
+  const formatter = new DateTimeFormatter(formatString);
+  return formatter.format(date);
 }
 
 /**