feat(format): Add formatting feature

projects/ng-date-interval/src/lib/date-interval.pipe.spec.ts

@@ -89,15 +89,27 @@ describe('DateIntervalPipe', () => {
     expect(result).toEqual(`From 6 to May 11, 2019`);
   });
 
-  it('should disgard same month/year when format specified', () => {
-    const dates = [new Date('2019-05-06'), new Date('2019-05-11')];
-    const result = sut.transform(dates, 'backward', 'dd MMMM y');
-    expect(result).toEqual(`From 06 May 2019 to 11 May 2019`);
-  });
-
   it('should handle same year with single value', () => {
     const dates = [new Date('2019-05-06')];
     const result = sut.transform(dates);
     expect(result).toEqual(`Since May 6, 2019`);
   });
+
+  it('should handle same year with specified format (no days)', () => {
+    const dates = [new Date('2019-05-06'), new Date('2019-06-06')];
+    const result = sut.transform(dates, 'forward', 'MMM y');
+    expect(result).toEqual(`From May to Jun 2019`);
+  });
+
+  it('should handle same year with specified format (leading zero days)', () => {
+    const dates = [new Date('2019-05-06'), new Date('2019-06-06')];
+    const result = sut.transform(dates, 'forward', 'dd MMM y');
+    expect(result).toEqual(`From 06 May to 06 Jun 2019`);
+  });
+
+  it('should handle same year and same month with specified format (no days)', () => {
+    const dates = [new Date('2019-05-06'), new Date('2019-05-12')];
+    const result = sut.transform(dates, 'forward', 'MMM y');
+    expect(result).toEqual(`May 2019`);
+  });
 });

projects/ng-date-interval/src/lib/date-interval.pipe.ts

@@ -1,5 +1,5 @@
 import { Pipe, PipeTransform, LOCALE_ID, Inject, Input } from '@angular/core';
-import { ValidInput, InputDatesArray, DateOutlook } from '../types/types';
+import { ValidInput, InputDatesArray, DateOutlook, LocaleDateStringOptions } from '../types/types';
 import { formatDate } from '@angular/common';
 import sentences from '../langs';
 
@@ -33,25 +33,30 @@ export class DateIntervalPipe implements PipeTransform {
 
     const [startDate, endDate] = this.normalizedInput.map(this.formatDates.bind(this));
 
-    return !startDate && !endDate ? '' : this.interpolate(this.sentence, { startDate, endDate });
+    // If the specified format omits the days, but the interval is within
+    // the same month and year, return the formatted end date only
+    if (this.isSameYear && this.isSameMonth && !this.showDay) return endDate;
+
+    if (!startDate && !endDate) return '';
+
+    return this.interpolate(this.sentence, { startDate, endDate });
   }
 
   private formatDates(item: Date | string, index: number): string {
     if (!item) {
       return null;
     }
 
-    if (this.format !== defautDateFormat) {
-      return formatDate(item, this.format, this.locale);
-    }
-
     if (this.isSameYear && index === 0) {
-      const options = { month: 'short', day: 'numeric' };
+      let format = this.format === 'mediumDate' ? 'MMM d, y' : this.format;
+
+      format = this.removeDateFragment(format, 'y');
+
       if (this.isSameMonth) {
-        delete options.month;
+        format = this.removeDateFragment(format, 'm');
       }
 
-      return new Date(item).toLocaleDateString(this.locale, options);
+      return formatDate(item, format, this.locale);
     }
 
     return formatDate(item, this.format, this.locale);
@@ -85,6 +90,16 @@ export class DateIntervalPipe implements PipeTransform {
     return str;
   }
 
+  private removeDateFragment(str: string, key: 'd' | 'm' | 'y'): string {
+    const keyRegExp = new RegExp(`${key}`, 'gi');
+
+    return (str = str
+      .replace(keyRegExp, '')
+      .trim()
+      .replace(/^,+/, '')
+      .replace(/,+$/, ''));
+  }
+
   // GETTERS
 
   private get isSameYear(): boolean {
@@ -111,6 +126,10 @@ export class DateIntervalPipe implements PipeTransform {
     return month1 === month2;
   }
 
+  private get showDay(): boolean {
+    return this.format.toLowerCase().indexOf('d') > -1;
+  }
+
   private get sentence(): string {
     let type = 'default';
 

projects/ng-date-interval/src/types/types.ts

@@ -1,3 +1,8 @@
 export type InputDatesArray = Array<string | Date>;
 export type ValidInput = Array<string | Date> | string | Date;
 export type DateOutlook = 'backward' | 'forward';
+export interface LocaleDateStringOptions {
+  year?: 'numeric' | '2-digit';
+  month?: 'numeric' | '2-digit' | 'long' | 'short' | 'narrow';
+  day?: 'numeric' | '2-digit';
+}