fix: issue#24 do not modify input path-array

Author: sagold

lib/split.ts

@@ -19,7 +19,7 @@ function sanitizeAndDecodeProperty(property: string): string {
  */
 export function split(pointer: JsonPointer | JsonPath): JsonPath {
 	if (pointer == null || typeof pointer !== "string" || isRoot(pointer)) {
-		return Array.isArray(pointer) ? pointer : [];
+		return Array.isArray(pointer) ? pointer.slice() : [];
 	}
 	const sanitize =
 		pointer.indexOf("#") >= 0

test/unit/get.test.ts

@@ -53,6 +53,14 @@ describe("pointer.get", () => {
         assert.equal(result, "propertyValue");
     });
 
+    it("should not modify input path-array", () => {
+        const path = ["property", "value"];
+        const result = get({ property: { value: "propertyValue" } }, path);
+        assert.equal(result, "propertyValue");
+
+        assert.deepEqual(path, ["property", "value"]);
+    });
+
     it("should return 'defaultValue' if property does not exist", () => {
         const result = get(
             { property: { value: "propertyValue" } },

test/unit/remove.test.ts

@@ -39,6 +39,13 @@ describe("remove", () => {
         assert(isObject(result.a.c));
     });
 
+    it("should not modify input path-array", () => {
+        const path = ["a", "b"];
+        const result = remove({ a: { b: {}, c: {} } }, path);
+
+        assert.deepEqual(path, ["a", "b"]);
+    });
+
     it("should ignore invalid paths", () => {
         const result = remove({ a: { b: {}, c: {} } }, "/a/d/c");
 

test/unit/set.test.ts

@@ -179,6 +179,17 @@ describe("pointer.set", () => {
         assert.equal(result.array[1].valid, true)
     });
 
+    it("should not modify input path-array", () => {
+        const path = ["array", "[1]", "valid"];
+        const result = set<{ array?: any[] }>(
+            {},
+            path,
+            true
+        );
+
+        assert.deepEqual(path, ["array", "[1]", "valid"]);
+    });
+
     describe("# (uri fragment)", () => {
         it("should add value on the given path", () => {
             const result = set<{ path?: { to?: { property?: boolean } } }>(

test/unit/split.test.ts

@@ -41,6 +41,14 @@ describe("pointer.split", () => {
         assert.deepEqual(result, ["a", "b"]);
     });
 
+    it("should return copy of input array", () => {
+        const path = ["a", "b"];
+        const result = split(["a", "b"]);
+
+        assert.deepEqual(result, path);
+        assert.notEqual(result, path);
+    });
+
     it("should return path properties in array", () => {
         const result = split("/my/path");