From 183637b87f928c3d62991de764d15228f1a19338 Mon Sep 17 00:00:00 2001
From: Jukka Kurkela <jukka.kurkela@gmail.com>
Date: Tue, 10 Nov 2020 17:34:31 +0200
Subject: [PATCH] Add tests and clean up resolveObjectKey helper (#8028)

* Add tests and clean up resolveObjectKey helper

* Change the optimized path to comply with thests
---
 src/helpers/helpers.core.js      | 18 ++++---
 test/specs/helpers.core.tests.js | 83 ++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+), 7 deletions(-)

diff --git a/src/helpers/helpers.core.js b/src/helpers/helpers.core.js
index 89bf473bd..7066e578e 100644
--- a/src/helpers/helpers.core.js
+++ b/src/helpers/helpers.core.js
@@ -274,17 +274,21 @@ export function _deprecated(scope, value, previous, current) {
 }
 
 export function resolveObjectKey(obj, key) {
-	if (key.length < 3) {
-		return obj[key];
+	// Special cases for `x` and `y` keys. It's quite a lot faster to aceess this way.
+	// Those are the default keys Chart.js is resolving, so it makes sense to be fast.
+	if (key === 'x') {
+		return obj.x;
+	}
+	if (key === 'y') {
+		return obj.y;
 	}
 	const keys = key.split('.');
-	for (let i = 0, n = keys.length; i < n; ++i) {
+	for (let i = 0, n = keys.length; i < n && obj; ++i) {
 		const k = keys[i];
-		if (k in obj) {
-			obj = obj[k];
-		} else {
-			return;
+		if (!k) {
+			break;
 		}
+		obj = obj[k];
 	}
 	return obj;
 }
diff --git a/test/specs/helpers.core.tests.js b/test/specs/helpers.core.tests.js
index 0f38613f1..b491686f8 100644
--- a/test/specs/helpers.core.tests.js
+++ b/test/specs/helpers.core.tests.js
@@ -374,4 +374,87 @@ describe('Chart.helpers.core', function() {
 			expect(output.o.a).not.toBe(a1);
 		});
 	});
+
+	describe('resolveObjectKey', function() {
+		it('should resolve empty key to root object', function() {
+			const obj = {test: true};
+			expect(helpers.resolveObjectKey(obj, '')).toEqual(obj);
+		});
+		it('should resolve one level', function() {
+			const obj = {
+				bool: true,
+				str: 'test',
+				int: 42,
+				obj: {name: 'object'}
+			};
+			expect(helpers.resolveObjectKey(obj, 'bool')).toEqual(true);
+			expect(helpers.resolveObjectKey(obj, 'str')).toEqual('test');
+			expect(helpers.resolveObjectKey(obj, 'int')).toEqual(42);
+			expect(helpers.resolveObjectKey(obj, 'obj')).toEqual(obj.obj);
+		});
+		it('should resolve multiple levels', function() {
+			const obj = {
+				child: {
+					level: 1,
+					child: {
+						level: 2,
+						child: {
+							level: 3
+						}
+					}
+				}
+			};
+			expect(helpers.resolveObjectKey(obj, 'child.level')).toEqual(1);
+			expect(helpers.resolveObjectKey(obj, 'child.child.level')).toEqual(2);
+			expect(helpers.resolveObjectKey(obj, 'child.child.child.level')).toEqual(3);
+		});
+		it('should resolve circular reference', function() {
+			const root = {};
+			const child = {root};
+			child.child = child;
+			root.child = child;
+			expect(helpers.resolveObjectKey(root, 'child')).toEqual(child);
+			expect(helpers.resolveObjectKey(root, 'child.child.child.child.child.child')).toEqual(child);
+			expect(helpers.resolveObjectKey(root, 'child.child.root')).toEqual(root);
+		});
+		it('should break at empty key', function() {
+			const obj = {
+				child: {
+					level: 1,
+					child: {
+						level: 2,
+						child: {
+							level: 3
+						}
+					}
+				}
+			};
+			expect(helpers.resolveObjectKey(obj, 'child..level')).toEqual(obj.child);
+			expect(helpers.resolveObjectKey(obj, 'child.child.level...')).toEqual(2);
+			expect(helpers.resolveObjectKey(obj, '.')).toEqual(obj);
+			expect(helpers.resolveObjectKey(obj, '..')).toEqual(obj);
+		});
+		it('should resolve undefined', function() {
+			const obj = {
+				child: {
+					level: 1,
+					child: {
+						level: 2,
+						child: {
+							level: 3
+						}
+					}
+				}
+			};
+			expect(helpers.resolveObjectKey(obj, 'level')).toEqual(undefined);
+			expect(helpers.resolveObjectKey(obj, 'child.level.a')).toEqual(undefined);
+		});
+		it('should throw on invalid input', function() {
+			expect(() => helpers.resolveObjectKey(undefined, undefined)).toThrow();
+			expect(() => helpers.resolveObjectKey({}, null)).toThrow();
+			expect(() => helpers.resolveObjectKey({}, false)).toThrow();
+			expect(() => helpers.resolveObjectKey({}, true)).toThrow();
+			expect(() => helpers.resolveObjectKey({}, 1)).toThrow();
+		});
+	});
 });
-- 
2.47.2