fix: support RegExp flags added after es2017 (s, d, v) in clone and patch

packages/jsondiffpatch/src/clone.ts

@@ -1,5 +1,5 @@
 function cloneRegExp(re: RegExp) {
-	const regexMatch = /^\/(.*)\/([gimyu]*)$/.exec(re.toString());
+	const regexMatch = /^\/(.*)\/([dgimsuvy]*)$/.exec(re.toString());
 	if (!regexMatch) {
 		throw new Error("Invalid RegExp");
 	}

packages/jsondiffpatch/src/filters/trivial.ts

@@ -88,7 +88,7 @@ export const patchFilter: Filter<PatchContext> =
 		}
 		if (nonNestedDelta.length === 2) {
 			if (context.left instanceof RegExp) {
-				const regexArgs = /^\/(.*)\/([gimyu]+)$/.exec(
+				const regexArgs = /^\/(.*)\/([dgimsuvy]+)$/.exec(
 					nonNestedDelta[1] as string,
 				);
 				if (regexArgs?.[1]) {

packages/jsondiffpatch/test/examples/diffpatch.ts

@@ -17,6 +17,11 @@ type ExampleGroup = Example[];
 
 const exampleDate = () => new Date(2020, 10, 30, 15, 10, 3);
 
+// Built via the constructor rather than a `/…/s` literal so these compile under
+// the repo's es6 target (the `s` flag postdates es6 and a literal would error).
+const regExpWithFlags = (source: string, flags: string) =>
+	new RegExp(source, flags);
+
 const atomicValues: ExampleGroup = [
 	// undefined
 	{
@@ -464,6 +469,13 @@ const atomicValues: ExampleGroup = [
 		delta: ["/regex/g", "/another regex/gi"],
 		reverse: ["/another regex/gi", "/regex/g"],
 	},
+	{
+		name: "RegExp -> RegExp (dotAll flag)",
+		left: regExpWithFlags("regex", "s"),
+		right: regExpWithFlags("another regex", "s"),
+		delta: ["/regex/s", "/another regex/s"],
+		reverse: ["/another regex/s", "/regex/s"],
+	},
 
 	// object
 	{

packages/jsondiffpatch/test/index.spec.ts

@@ -137,6 +137,16 @@ describe("DiffPatcher", () => {
 				pattern: /expr/gim,
 			});
 		});
+		it("clones RegExp with flags added after es2017 (s, d, v)", () => {
+			// `s` (es2018), `d` (es2022) and `v` (es2024) all postdate the repo's
+			// es6 target, so build via the constructor with a non-literal flag
+			// (a `/…/s` literal would not compile).
+			for (const flag of ["s", "d", "v"]) {
+				const pattern = new RegExp("expr", flag);
+				const cloned = jsondiffpatch.clone({ pattern });
+				expect(cloned).toEqual({ pattern });
+			}
+		});
 	});
 
 	describe("using cloneDiffValues", () => {