refactor client models to use lokijs

shared/utils/date_range.js

@@ -0,0 +1,69 @@
+class DateRange {
+
+  static addRange(new_range, ranges){
+    var gaps_filled = [], new_ranges = [],
+      start = new_range[0], end = new_range[1];
+    if (start === undefined && end === undefined && ranges.length === 0){
+      gaps_filled = [undefined, undefined];
+      new_ranges = [[undefined, undefined]];
+    } else if (ranges.length === 0){
+      gaps_filled = [new_range];
+      new_ranges = [new_range]
+    } else {
+      var covered = false,
+        last_start = start,
+        last_end = start;
+
+      ranges.forEach((range, i)=>{
+        if (covered){ new_ranges.push(range); return true; }
+        if (DateUtil.lte(start, range[0])){
+          if (end && !DateUtil.eq(end, range[0]) && DateUtil.lte(end, range[0])){
+            new_ranges.push([last_start, end]);
+            new_ranges.push(range);
+            gaps_filled.push([last_end, end]);
+            covered = true;
+          } else if (end && !DateUtil.gte(end, range[1])) {
+            new_ranges.push([last_start, range[1]]);
+            if (range[0] && !DateUtil.eq(last_end, range[0])){ gaps_filled.push([last_end, range[0]]); }
+            covered = true
+          } else {
+            if (range[0] && !DateUtil.eq(last_end, range[0])) gaps_filled.push([last_end, range[0]]);
+            last_end = range[1]
+          }
+        } else if (start && DateUtil.gte(range[1], start)){
+            if (!DateUtil.eq(end, range[1]) && DateUtil.gte(end, range[1])){
+              last_start = range[0];
+              last_end = range[1];
+            } else {
+              new_ranges.push(range);
+              covered = true;
+            }
+        } else { new_ranges.push(range); }
+      });
+      if (!covered) {
+        new_ranges.push([last_start, end]);
+        if (!DateUtil.eq(last_end, end)) gaps_filled.push([last_end, end]);
+      }
+    }
+
+    return { gaps_filled: gaps_filled, new_ranges: new_ranges }
+  }
+
+  static gte(date1, date2){
+    return (date1 === undefined || (date2 !== undefined && date1 >= date2));
+  }
+
+  static lte(date1, date2){
+    return (date1 === undefined || (date2 !== undefined && date1 <= date2));
+  }
+
+  static eq(date1, date2){
+    return (date1 !== undefined && date2 !== undefined && date1.getTime() === date2.getTime()) || date1 === undefined && date2 === undefined
+  }
+
+  static add(date, s){
+    return new Date(date.getTime() + s);
+  }
+
+}
+export default DateUtil;