feat(api): Report.merge() can merge async results

ext · ext · commit 35689fc10b8e · 2023-12-25T04:59:45.000+01:00
diff --git a/etc/browser.api.md b/etc/browser.api.md
@@ -935,6 +935,7 @@ export class Reporter {
     // (undocumented)
     protected isValid(): boolean;
     static merge(reports: Report_2[]): Report_2;
+    static merge(reports: Promise<Report_2[]> | Array<Promise<Report_2>>): Promise<Report_2>;
     // (undocumented)
     protected result: Record<string, DeferredMessage[]>;
     // (undocumented)
diff --git a/etc/index.api.md b/etc/index.api.md
@@ -1028,6 +1028,7 @@ export class Reporter {
     // (undocumented)
     protected isValid(): boolean;
     static merge(reports: Report_2[]): Report_2;
+    static merge(reports: Promise<Report_2[]> | Array<Promise<Report_2>>): Promise<Report_2>;
     // (undocumented)
     protected result: Record<string, DeferredMessage[]>;
     // (undocumented)
diff --git a/src/reporter.spec.ts b/src/reporter.spec.ts
@@ -48,6 +48,56 @@ describe("Reporter", () => {
 			expect(merged.errorCount).toBe(4);
 			expect(merged.warningCount).toBe(0);
 		});
+
+		it("should handle promise with results", async () => {
+			expect.assertions(3);
+			const merged = await Reporter.merge(
+				Promise.resolve([
+					{
+						valid: false,
+						results: [createResult("foo", ["fred", "barney"])],
+						errorCount: 1,
+						warningCount: 0,
+					},
+					{
+						valid: true,
+						results: [createResult("bar", ["wilma"])],
+						errorCount: 0,
+						warningCount: 1,
+					},
+				]),
+			);
+			expect(merged.valid).toBeFalsy();
+			expect(merged.results[0].filePath).toBe("foo");
+			expect(merged.results[1].filePath).toBe("bar");
+		});
+
+		it("should handle array of promises", async () => {
+			expect.assertions(3);
+			const merged = await Reporter.merge([
+				Promise.resolve({
+					valid: false,
+					results: [createResult("foo", ["fred", "barney"])],
+					errorCount: 1,
+					warningCount: 0,
+				}),
+				Promise.resolve({
+					valid: true,
+					results: [createResult("bar", ["wilma"])],
+					errorCount: 0,
+					warningCount: 1,
+				}),
+			]);
+			expect(merged.valid).toBeFalsy();
+			expect(merged.results[0].filePath).toBe("foo");
+			expect(merged.results[1].filePath).toBe("bar");
+		});
+
+		it("should handle empty array", async () => {
+			expect.assertions(1);
+			const merged = Reporter.merge([]);
+			expect(merged.results).toHaveLength(0);
+		});
 	});
 
 	describe("save()", () => {
diff --git a/src/reporter.ts b/src/reporter.ts
@@ -2,6 +2,7 @@ import { Severity } from "./config";
 import { type Location, type Source } from "./context";
 import { type Rule } from "./rule";
 import { type DOMNode } from "./dom";
+import { isThenable } from "./utils";
 
 /**
  * Reported error message.
@@ -58,6 +59,13 @@ function freeze(src: DeferredMessage): Message {
 	};
 }
 
+function isThenableArray<T>(value: T[] | Array<Promise<T>>): value is Array<Promise<T>> {
+	if (value.length === 0) {
+		return false;
+	}
+	return isThenable(value[0]);
+}
+
 /**
  * @public
  */
@@ -100,8 +108,29 @@ export class Reporter {
 
 	/**
 	 * Merge two or more reports into a single one.
+	 *
+	 * @param reports- Reports to merge.
+	 * @returns A merged report.
+	 */
+	public static merge(reports: Report[]): Report;
+
+	/**
+	 * Merge two or more reports into a single one.
+	 *
+	 * @param reports- Reports to merge.
+	 * @returns A promise resolved with the merged report.
 	 */
-	public static merge(reports: Report[]): Report {
+	public static merge(reports: Promise<Report[]> | Array<Promise<Report>>): Promise<Report>;
+
+	public static merge(
+		reports: Report[] | Promise<Report[]> | Array<Promise<Report>>,
+	): Report | Promise<Report> {
+		if (isThenable(reports)) {
+			return reports.then((reports) => this.merge(reports));
+		}
+		if (isThenableArray(reports)) {
+			return Promise.all(reports).then((reports) => this.merge(reports));
+		}
 		const valid = reports.every((report) => report.valid);
 		const merged: Record<string, Result> = {};
 		reports.forEach((report: Report) => {
