Merge pull request #15 from subeshb1/feature/add_parse

Feature/add parse

src/nepali-date-converter.ts

@@ -4,7 +4,8 @@ import {
   IYearMonthDate,
   IAdBs,
   format,
-  Language
+  Language,
+  parse
 } from './nepali-date-helper'
 
 const dateSymbol = Symbol('Date')
@@ -36,6 +37,9 @@ export default class NepaliDate {
           this[convertToBSMethod](new Date(argument))
           break
         case 'string':
+          const { date, year, month } = parse(argument)
+          this[setDayYearMonth](year, month, date)
+          this[convertToADMethod]()
           break
         case 'object':
           if (argument instanceof Date) {
@@ -139,13 +143,15 @@ export default class NepaliDate {
     }
   }
 
-  format(formatString: string, language: Language): string {
+  format(formatString: string, language: Language = NepaliDate.language): string {
     return format(this.getBS(), formatString, language)
   }
 
-  static parse() {
-    return new NepaliDate()
+  static parse(dateString: string): NepaliDate {
+    const { date, year, month } = parse(dateString)
+    return new NepaliDate(year, month, date)
   }
+
   static now() {
     return new NepaliDate()
   }

src/nepali-date-helper.ts

@@ -1647,3 +1647,26 @@ export function format(bsDate: IYearMonthDate, stringFormat: string, language: L
     })
     .replace(/\\/g, '')
 }
+
+export function parse(dateString: string): IYearMonthDate {
+  const OFFICIAL_FORMAT = /(\d{4})\s*([/-]|\s+)\s*(\d{1,2})\s*([/-]|\s+)\s*(\d{1,2})/
+  const GEORGIAN_FORMAT = /(\d{1,2})\s*([/-]|\s+)\s*(\d{1,2})\s*([/-]|\s+)\s*(\d{4})/
+  let match: RegExpMatchArray | null
+  match = dateString.match(OFFICIAL_FORMAT)
+  if (match !== null) {
+    return {
+      year: parseInt(match[1], 10),
+      month: parseInt(match[3], 10) - 1,
+      date: parseInt(match[5], 10)
+    }
+  }
+  match = dateString.match(GEORGIAN_FORMAT)
+  if (match !== null) {
+    return {
+      year: parseInt(match[5], 10),
+      month: parseInt(match[3], 10) - 1,
+      date: parseInt(match[1], 10)
+    }
+  }
+  throw new Error('Invalid date format')
+}