Add parse/stringify for EXT-X-DATERANGE CUE attribute (#165)

* Add parse/stringify for EXT-X-DATERANGE CUE attribute

* clean code

* clean code

Author: bbert

parse.ts

@@ -563,6 +563,7 @@ function parseSegment(lines: Line[], uri: string, start: number, end: number, me
         id: attributes['ID'],
         classId: attributes['CLASS'],
         start: attributes['START-DATE'],
+        cue: attributes['CUE'],
         end: attributes['END-DATE'],
         duration: attributes['DURATION'],
         plannedDuration: attributes['PLANNED-DURATION'],

stringify.ts

@@ -408,6 +408,9 @@ function buildDateRange(dateRange: DateRange) {
   if (dateRange.start) {
     attrs.push(`START-DATE="${utils.formatDate(dateRange.start)}"`);
   }
+  if (dateRange.cue) {
+    attrs.push(`CUE="${dateRange.cue}"`);
+  }
   if (dateRange.end) {
     attrs.push(`END-DATE="${utils.formatDate(dateRange.end)}"`);
   }

types.ts

@@ -204,6 +204,7 @@ class DateRange {
   id: string;
   classId?: string;
   start?: Date;
+  cue?: string;
   end?: Date;
   duration?: number;
   plannedDuration?: number;
@@ -214,6 +215,7 @@ class DateRange {
     id, // required
     classId, // required if endOnNext is true
     start,
+    cue,
     end,
     duration,
     plannedDuration,
@@ -226,6 +228,7 @@ class DateRange {
     this.id = id;
     this.classId = classId;
     this.start = start;
+    this.cue = cue;
     this.end = end;
     this.duration = duration;
     this.plannedDuration = plannedDuration;