New: Support reference following a date

src/locales/en/configuration.ts

@@ -20,7 +20,9 @@ import ENRelativeDateFormatParser from "./parsers/ENRelativeDateFormatParser";
 
 import SlashDateFormatParser from "../../common/parsers/SlashDateFormatParser";
 import ENTimeUnitCasualRelativeFormatParser from "./parsers/ENTimeUnitCasualRelativeFormatParser";
-import ENMergeRelativeDateRefiner from "./refiners/ENMergeRelativeDateRefiner";
+import ENMergeRelativeAfterDateRefiner from "./refiners/ENMergeRelativeAfterDateRefiner";
+import ENMergeRelativeFollowByDateRefiner from "./refiners/ENMergeRelativeFollowByDateRefiner";
+import OverlapRemovalRefiner from "../../common/refiners/OverlapRemovalRefiner";
 
 export default class ENDefaultConfiguration {
     /**
@@ -58,10 +60,15 @@ export default class ENDefaultConfiguration {
                     new ENTimeUnitAgoFormatParser(strictMode),
                     new ENTimeUnitLaterFormatParser(strictMode),
                 ],
-                refiners: [new ENMergeRelativeDateRefiner(), new ENMergeDateTimeRefiner()],
+                refiners: [new ENMergeDateTimeRefiner()],
             },
             strictMode
         );
+        // These relative-dates consideration should be done before other common refiners.
+        options.refiners.unshift(new ENMergeRelativeFollowByDateRefiner());
+        options.refiners.unshift(new ENMergeRelativeAfterDateRefiner());
+        options.refiners.unshift(new OverlapRemovalRefiner());
+
         // Re-apply the date time refiner again after the timezone refinement and exclusion in common refiners.
         options.refiners.push(new ENMergeDateTimeRefiner());
         // Keep the date range refiner at the end (after all other refinements).

src/locales/en/refiners/ENMergeRelativeAfterDateRefiner.ts

@@ -0,0 +1,46 @@
+import { MergingRefiner } from "../../../common/abstractRefiners";
+import { ParsingComponents, ParsingResult, ReferenceWithTimezone } from "../../../results";
+import { parseTimeUnits } from "../constants";
+import { reverseTimeUnits } from "../../../utils/timeunits";
+
+function IsPositiveFollowingReference(result: ParsingResult): boolean {
+    return result.text.match(/^[+-]/i) != null;
+}
+
+function IsNegativeFollowingReference(result: ParsingResult): boolean {
+    return result.text.match(/^-/i) != null;
+}
+
+/**
+ * Merges a relative data/time that comes after an absolute date.
+ * - [2020-02-13] [+2 weeks]
+ * - [next tuesday] [+10 days]
+ */
+export default class ENMergeRelativeAfterDateRefiner extends MergingRefiner {
+    shouldMergeResults(textBetween: string, currentResult: ParsingResult, nextResult: ParsingResult): boolean {
+        if (!textBetween.match(/^\s*$/i)) {
+            return false;
+        }
+
+        return IsPositiveFollowingReference(nextResult) || IsNegativeFollowingReference(nextResult);
+    }
+
+    mergeResults(textBetween: string, currentResult: ParsingResult, nextResult: ParsingResult, context): ParsingResult {
+        let timeUnits = parseTimeUnits(nextResult.text);
+        if (IsNegativeFollowingReference(nextResult)) {
+            timeUnits = reverseTimeUnits(timeUnits);
+        }
+
+        const components = ParsingComponents.createRelativeFromReference(
+            new ReferenceWithTimezone(currentResult.start.date()),
+            timeUnits
+        );
+
+        return new ParsingResult(
+            currentResult.reference,
+            currentResult.index,
+            `${currentResult.text}${textBetween}${nextResult.text}`,
+            components
+        );
+    }
+}

src/locales/en/refiners/ENMergeRelativeDateRefiner.ts → src/locales/en/refiners/ENMergeRelativeFollowByDateRefiner.ts

@@ -12,11 +12,11 @@ function hasImpliedLaterReferenceDate(result: ParsingResult): boolean {
 }
 
 /**
- * Merges an absolute date with a relative date.
- * - 2 weeks before 2020-02-13
- * - 2 days after next Friday
+ * Merges a relative data/time that follow by an absolute date.
+ * - [2 weeks before] [2020-02-13]
+ * - [2 days after] [next Friday]
  */
-export default class ENMergeRelativeDateRefiner extends MergingRefiner {
+export default class ENMergeRelativeFollowByDateRefiner extends MergingRefiner {
     patternBetween(): RegExp {
         return /^\s*$/i;
     }

test/en/en_time_units_later.test.ts

@@ -320,3 +320,25 @@ test("Test - After with reference", () => {
         expect(result.start.get("day")).toBe(18);
     });
 });
+
+test("Test - Plus after reference", () => {
+    testSingleCase(chrono, "next tuesday +10 days", new Date(2023, 12 - 1, 29), (result) => {
+        expect(result.start.get("year")).toBe(2024);
+        expect(result.start.get("month")).toBe(1);
+        expect(result.start.get("day")).toBe(12);
+    });
+
+    testSingleCase(chrono, "2023-12-29 -10days", new Date(2023, 12 - 1, 29), (result) => {
+        expect(result.start.get("year")).toBe(2023);
+        expect(result.start.get("month")).toBe(12);
+        expect(result.start.get("day")).toBe(19);
+    });
+
+    testSingleCase(chrono, "now + 40minutes", new Date(2023, 12 - 1, 29, 8, 30), (result) => {
+        expect(result.start.get("year")).toBe(2023);
+        expect(result.start.get("month")).toBe(12);
+        expect(result.start.get("day")).toBe(29);
+        expect(result.start.get("hour")).toBe(9);
+        expect(result.start.get("minute")).toBe(10);
+    });
+});