GFE Deep Clone Problem #103
Conversation
📝 WalkthroughWalkthroughA new Deep Clone utility function is added to the GFE75 JavaScript Utilities collection, advancing progress from 4/75 to 5/75 completed problems. The addition includes TypeScript implementation, unit tests, and documentation. Progress tracking across multiple README files has been updated accordingly. Changes
Estimated code review effort🎯 3 (Moderate) | ⏱️ ~22 minutes Poem
Pre-merge checks and finishing touches❌ Failed checks (1 warning)
✅ Passed checks (2 passed)
✨ Finishing touches
🧪 Generate unit tests (beta)
Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out. Comment |
|
Claude finished @pertrai1's task in 1m 9s —— View job Code Review Complete ✅I've reviewed the GreatFrontEnd Deep Clone solution. Here's my comprehensive feedback: 1. Correctness ✅The solution correctly implements deep cloning for JSON-serializable values. The logic handles:
However, there are critical edge cases missing: Missing Edge CasesThe current implementation doesn't handle several important scenarios:
const obj = { a: 1 };
obj.self = obj;
deepClone(obj); // Stack overflow!
deepClone({}) // Should return {}
deepClone([]) // Should return []
2. Complexity AnalysisTime Complexity: O(n) where n is the total number of values (primitives + objects + arrays) in the entire nested structure. Every value is visited exactly once. Space Complexity: O(d + n) where:
Why: Each recursive call adds a frame to the call stack (depth), and we create a complete copy of all values (size). 3. Code QualityStrengths:
Suggestions:Add inline comments for clarity (greatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.ts:1-11): export function deepClone<T>(value: T): T {
// Base case: primitives and null are returned as-is
if (typeof value !== 'object' || value === null) {
return value;
}
// Handle arrays by recursively cloning each element
if (Array.isArray(value)) {
return value.map((val) => deepClone(val)) as T;
}
// Handle objects by recursively cloning each property
return Object.fromEntries(
Object.entries(value).map(([key, val]) => [key, deepClone(val)])
) as T;
}4. Testing ConsiderationsThe test suite covers basic scenarios but is missing important cases: Missing Test Cases: // Empty structures
it('empty objects and arrays', () => {
expect(deepClone({})).toEqual({});
expect(deepClone([])).toEqual([]);
});
// Null values
it('null values', () => {
expect(deepClone(null)).toBeNull();
expect(deepClone({ a: null })).toEqual({ a: null });
});
// Arrays of primitives
it('arrays of primitives', () => {
const arr = [1, 2, 3];
const cloned = deepClone(arr);
cloned[0] = 999;
expect(arr[0]).toBe(1);
});
// Mixed nested structures
it('arrays containing objects', () => {
const data = [{ id: 1 }, { id: 2 }];
const cloned = deepClone(data);
cloned[0].id = 999;
expect(data[0].id).toBe(1);
});5. Learning SummaryPattern: Recursive Traversal with Type CheckingThis solution uses a fundamental pattern in JavaScript: recursive tree traversal with runtime type checking. This pattern appears frequently in:
Key Insight 🔑The key insight is recognizing that deep cloning is a tree traversal problem. Each object/array is a node, and properties/elements are children. By recursively traversing and rebuilding the structure, we create an independent copy. The type checking order matters:
Why This Approach Works
Related Problems for Practice
Alternative ApproachesApproach 1: JSON.parse(JSON.stringify()) ⚡ Fastest for simple cases const deepClone = <T>(value: T): T => JSON.parse(JSON.stringify(value));
Approach 2: structuredClone() (Modern Web API) const deepClone = <T>(value: T): T => structuredClone(value);
Your recursive approach offers the best balance for:
Common Mistakes to Avoid
Overall AssessmentStrong foundation! The solution demonstrates understanding of:
For production use, you'd want to add:
For learning purposes, this is an excellent clean implementation that clearly shows the recursive pattern. Consider adding the missing test cases to strengthen your understanding of edge cases. |
|
@codex review |
1 similar comment
|
@codex review |
🧮 Solution AnalysisPR: GFE Deep Clone Problem 📊 Code Quality ResultsESLint Analysis
🔍 Complexity Analysisdeep-clone📋 Analysis Results: 🔍 Automated Complexity Analysis
File: greatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.ts Time ComplexityEstimated: O(n)
Space ComplexityEstimated: O(1) Data Structures Used
Code Metrics
Recommendations
deep-clone.test📋 Analysis Results: 🔍 Automated Complexity Analysis
File: greatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.test.ts Time ComplexityEstimated: Unknown
Space ComplexityEstimated: O(1) Code Metrics
Recommendations
💡 Analysis Tips
📁 Analysis Files CreatedDetailed analysis files have been automatically generated and committed to 🎯 Next Steps
Analysis generated for PR files only |
|
To use Codex here, create a Codex account and connect to github. |
1 similar comment
|
To use Codex here, create a Codex account and connect to github. |
✅ Test ResultsTests have been executed for this pull request. 📊 Coverage Summary
Check the workflow logs for detailed test output. |
|
🤖 Gemini Code Review (Model: Code Review: Deep Clone1. Pattern IdentificationThis solution primarily uses the Recursion pattern. Specifically, it employs a technique often called Structural Recursion or Deep Traversal. The algorithm recursively visits each nested object and array, making a new copy of each element or property value. 2. Complexity Verification
3. Key InsightThe key insight for a deep clone is to distinguish between primitive values and complex objects/arrays, and to handle complex types by recursively cloning their contents rather than just copying their references.
4. Edge Case AnalysisThe problem statement provides a crucial constraint: "You can assume the input only contains JSON-serializable values ( Given these constraints, the current solution correctly handles:
Edge cases not handled (but explicitly excluded by problem statement):
For the given problem constraints, the solution is robust. 5. Learning Points
6. Code QualityThe code quality is good:
Minor suggestion for robustness/defensive coding (optional, given problem constraints): While the problem guarantees JSON-serializable inputs, in a real-world scenario, 7. Alternative Approaches
The chosen recursive approach is idiomatic, clean, and perfectly suited for the given problem constraints and learning objectives. |
|
🤖 Gemini Code Review (Model: This is an excellent problem for understanding recursion and object manipulation in JavaScript. Let's break down your solution. 1. Pattern IdentificationThis solution primarily uses Recursion for Structural Cloning. It's a classic example of traversing a tree-like data structure (where objects and arrays form the nodes and their properties/elements are children) and creating a new, independent copy of it. 2. Complexity Verification
3. Key InsightThe key insight for deep cloning is recognizing that non-primitive values (objects and arrays) must be recursively processed to create truly independent copies.
This recursive decomposition allows the function to handle arbitrarily nested structures by breaking them down into simpler, clonable parts. 4. Edge Case AnalysisThe problem statement provides a crucial constraint: "You can assume the input only contains JSON-serializable values ( Let's analyze how your solution handles various edge cases within these constraints:
Edge Cases Not Handled (and why it's acceptable here):
5. Learning Points
6. Code QualityYour code is very clean, concise, and idiomatic for TypeScript/JavaScript.
Suggestions for Improvement (Minor):
7. Alternative Approaches
Your chosen recursive solution is the most elegant and efficient for the problem as stated, given its constraints. |
There was a problem hiding this comment.
Pull request overview
This PR adds a solution for the "Deep Clone" problem from GreatFrontEnd's GFE 75 collection. The implementation provides a TypeScript function that recursively clones JavaScript objects and arrays, handling JSON-serializable values while excluding special objects like Date, Regex, Map, or Set.
Key changes:
- Implements a recursive
deepClonefunction that handles primitives, arrays, and objects - Adds basic test coverage for primitive values, objects, and nested objects
- Updates progress trackers across README files to reflect the completion of 5/75 problems
Reviewed changes
Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.
Show a summary per file
| File | Description |
|---|---|
greatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.ts |
Core implementation using recursion with Array.isArray check and Object.entries/fromEntries for cloning |
greatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.test.ts |
Basic test suite covering primitives, objects, and nested objects |
greatfrontend/gfe-75/javascript-utilities/deep-clone/README.md |
Problem description with examples and constraints |
greatfrontend/gfe-75/javascript-utilities/README.md |
Moves Deep Clone from To Do to completed section |
greatfrontend/gfe-75/README.md |
Updates progress counter from 4/75 to 5/75 |
greatfrontend/README.md |
Removes progress section (simplification) |
README.md |
Updates GreatFrontEnd count from 7 to 8 and GFE 75 from 4/75 to 5/75 |
| describe('deepClone', () => { | ||
| it('primitive values', () => { | ||
| expect(deepClone('foo')).toEqual('foo'); | ||
| expect(deepClone(123)).toEqual(123); | ||
| }); | ||
|
|
||
| it('objects', () => { | ||
| const obj = { role: 'foo' }; | ||
| const clonedObj = deepClone(obj); | ||
| clonedObj.role = 'bar'; | ||
| expect(obj).toEqual({ role: 'foo' }); | ||
| }); | ||
|
|
||
| it('nested objects', () => { | ||
| const obj = { user: { role: 'admin', id: '123' } }; | ||
| const clonedObj = deepClone(obj); | ||
| clonedObj.user.role = 'bar'; | ||
| expect(obj).toEqual({ user: { role: 'admin', id: '123' } }); | ||
| }); | ||
| }); |
There was a problem hiding this comment.
The current implementation doesn't handle arrays within the test cases. While the implementation correctly handles arrays, there are no tests that verify arrays are deep cloned. Consider adding a test case for arrays, such as:
- Simple array cloning
- Nested arrays
- Arrays containing objects
- Mixed arrays with primitives and objects
This would ensure the array handling in line 5-6 of the implementation is properly tested.
| it('primitive values', () => { | ||
| expect(deepClone('foo')).toEqual('foo'); | ||
| expect(deepClone(123)).toEqual(123); | ||
| }); |
There was a problem hiding this comment.
The test suite is missing coverage for null values. The implementation specifically handles null in line 2 of deep-clone.ts, but there's no test verifying that deepClone(null) returns null correctly. Add a test case to verify null handling.
| it('objects', () => { | ||
| const obj = { role: 'foo' }; | ||
| const clonedObj = deepClone(obj); | ||
| clonedObj.role = 'bar'; | ||
| expect(obj).toEqual({ role: 'foo' }); | ||
| }); |
There was a problem hiding this comment.
Tests should verify that the cloned object is not the same reference as the original. While the current tests check that modifying the clone doesn't affect the original (which is good), they don't explicitly verify that the references are different. Consider adding assertions like expect(clonedObj).not.toBe(obj) to make this explicit.
| it('primitive values', () => { | ||
| expect(deepClone('foo')).toEqual('foo'); | ||
| expect(deepClone(123)).toEqual(123); | ||
| }); |
There was a problem hiding this comment.
Missing test coverage for boolean primitive values. The README examples mention that the function should handle boolean values, but the primitive values test only covers strings and numbers. Add a test case for boolean values (true/false).
![coderabbitai[bot]](https://avatars.githubusercontent.com/in/347564?s=60&v=4){kind=small}
There was a problem hiding this comment.
Actionable comments posted: 0
🧹 Nitpick comments (1)
greatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.test.ts (1)
4-23: Expand test coverage for additional JSON-serializable types.The current tests cover primitives (string, number), objects, and nested objects well. However, several JSON-serializable types mentioned in the requirements are not tested:
- Arrays (standalone and nested)
nullandundefined- Booleans
- Empty objects and arrays
- Mixed structures (objects containing arrays, arrays containing objects)
The README examples specifically demonstrate array handling, which should be tested.
🔎 Suggested additional test cases
+ it('null and undefined', () => { + expect(deepClone(null)).toBeNull(); + expect(deepClone(undefined)).toBeUndefined(); + }); + + it('boolean values', () => { + expect(deepClone(true)).toBe(true); + expect(deepClone(false)).toBe(false); + }); + + it('arrays', () => { + const arr = [1, 2, 3]; + const clonedArr = deepClone(arr); + clonedArr.push(4); + expect(arr).toEqual([1, 2, 3]); + expect(clonedArr).toEqual([1, 2, 3, 4]); + }); + + it('nested arrays and objects', () => { + const obj = { foo: [{ bar: 'baz' }] }; + const clonedObj = deepClone(obj); + clonedObj.foo[0].bar = 'qux'; + expect(obj.foo[0].bar).toBe('baz'); + }); + + it('empty structures', () => { + expect(deepClone({})).toEqual({}); + expect(deepClone([])).toEqual([]); + });Based on learnings, comprehensive test coverage helps verify parameter validation and edge case handling.
📜 Review details
Configuration used: defaults
Review profile: CHILL
Plan: Pro
📒 Files selected for processing (7)
README.mdgreatfrontend/README.mdgreatfrontend/gfe-75/README.mdgreatfrontend/gfe-75/javascript-utilities/README.mdgreatfrontend/gfe-75/javascript-utilities/deep-clone/README.mdgreatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.test.tsgreatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.ts
💤 Files with no reviewable changes (1)
- greatfrontend/README.md
🧰 Additional context used
📓 Path-based instructions (5)
**/*.ts
📄 CodeRabbit inference engine (AGENTS.md)
**/*.ts: Use explicit type annotations for function parameters and return types in TypeScript solutions
Follow strict TypeScript configuration with ES2020 target and CommonJS modules in TypeScript solutions
Enforce full type safety in TypeScript solutions
Files:
greatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.tsgreatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.test.ts
**/*.{js,ts}
📄 CodeRabbit inference engine (AGENTS.md)
**/*.{js,ts}: Use clear, descriptive variable names across all solutions
Add comments for non-obvious logic or algorithm steps in code
Keep functions focused and single-purpose across all solutions
Prefer readability over cleverness in code implementation
**/*.{js,ts}: Use descriptive variable names; single letters likei,j,kare acceptable for loop iterators and standard mathematical contexts
Add comments for complex logic, but prefer self-documenting code with clear logic
Minimize external dependencies and keep solutions self-contained
**/*.{js,ts}: Use clear, descriptive variable names (not just i, j, k unless in simple loops) and add comments for non-obvious logic or algorithm steps
Keep functions focused and single-purpose, preferring readability over cleverness
Use const by default, let only when reassignment needed; avoid var except for LeetCode solution function definitions
Use modern ES6+ syntax (arrow functions, destructuring, spread operators) where appropriate
Prefer built-in methods (.map(), .filter(), .reduce()) when appropriate and use strict equality (===) over loose equality (==)
Files:
greatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.tsgreatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.test.ts
**/*.{ts,tsx}
📄 CodeRabbit inference engine (.github/copilot-instructions.md)
**/*.{ts,tsx}: Use explicit type annotations for function parameters and return types in TypeScript
Follow strict TypeScript configuration as defined in tsconfig.json with ES2020 target and CommonJS modules
Files:
greatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.tsgreatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.test.ts
**/*.md
📄 CodeRabbit inference engine (AGENTS.md)
**/*.md: Create comprehensive documentation guides for arrays, trees, graphs, heaps, and other data structures
Document reusable code templates for common algorithmic patterns
Maintain Big O complexity cheatsheets and references
Files:
README.mdgreatfrontend/gfe-75/javascript-utilities/deep-clone/README.mdgreatfrontend/gfe-75/README.mdgreatfrontend/gfe-75/javascript-utilities/README.md
**/README.md
📄 CodeRabbit inference engine (CLAUDE.md)
Each problem directory should include a README.md containing: problem title and difficulty badge, link to the problem on the respective platform, problem description, examples and constraints
Files:
README.mdgreatfrontend/gfe-75/javascript-utilities/deep-clone/README.mdgreatfrontend/gfe-75/README.mdgreatfrontend/gfe-75/javascript-utilities/README.md
🧠 Learnings (6)
📚 Learning: 2025-12-02T17:56:01.747Z
Learnt from: CR
Repo: pertrai1/coding-challenges PR: 0
File: CLAUDE.md:0-0
Timestamp: 2025-12-02T17:56:01.747Z
Learning: Applies to GreatFrontEnd/**/*.{js,ts} : Evaluate the public API for clarity and usability, check for consistent naming conventions, verify parameter validation and error handling in GreatFrontEnd solutions
Applied to files:
README.mdgreatfrontend/gfe-75/README.mdgreatfrontend/gfe-75/javascript-utilities/README.md
📚 Learning: 2025-12-02T17:56:01.747Z
Learnt from: CR
Repo: pertrai1/coding-challenges PR: 0
File: CLAUDE.md:0-0
Timestamp: 2025-12-02T17:56:01.747Z
Learning: Applies to GreatFrontEnd/**/*.{js,ts} : Check for unnecessary re-renders or DOM manipulations, verify efficient data structure usage for UI updates in GreatFrontEnd solutions
Applied to files:
greatfrontend/gfe-75/README.mdgreatfrontend/gfe-75/javascript-utilities/README.md
📚 Learning: 2025-12-02T17:56:01.747Z
Learnt from: CR
Repo: pertrai1/coding-challenges PR: 0
File: CLAUDE.md:0-0
Timestamp: 2025-12-02T17:56:01.747Z
Learning: Applies to GreatFrontEnd/**/*.{js,ts} : Look for debouncing/throttling where appropriate and consider memory leaks (event listeners, timers, closures) in GreatFrontEnd solutions
Applied to files:
greatfrontend/gfe-75/javascript-utilities/README.md
📚 Learning: 2025-12-02T17:56:01.747Z
Learnt from: CR
Repo: pertrai1/coding-challenges PR: 0
File: CLAUDE.md:0-0
Timestamp: 2025-12-02T17:56:01.747Z
Learning: Applies to **/*.{js,ts} : Prefer built-in methods (.map(), .filter(), .reduce()) when appropriate and use strict equality (===) over loose equality (==)
Applied to files:
greatfrontend/gfe-75/javascript-utilities/README.md
📚 Learning: 2025-11-26T14:46:46.097Z
Learnt from: CR
Repo: pertrai1/coding-challenges PR: 0
File: .github/copilot-instructions.md:0-0
Timestamp: 2025-11-26T14:46:46.097Z
Learning: Applies to [0-9]*-*/*.{js,ts} : Use standard algorithmic patterns (two pointers, sliding window, hash maps, DFS, BFS, DP) and leverage appropriate data structures (Map, Set, arrays)
Applied to files:
greatfrontend/gfe-75/javascript-utilities/README.md
📚 Learning: 2025-11-24T23:55:10.338Z
Learnt from: CR
Repo: pertrai1/coding-challenges PR: 0
File: AGENTS.md:0-0
Timestamp: 2025-11-24T23:55:10.338Z
Learning: Applies to **/*.js : Keep JavaScript solutions concise and focused on the algorithm
Applied to files:
greatfrontend/gfe-75/javascript-utilities/README.md
🪛 LanguageTool
greatfrontend/gfe-75/javascript-utilities/deep-clone/README.md
[style] ~3-~3: Consider using a different adverb to strengthen your wording.
Context: ... a copy of JavaScript value, leading to a completely new value that has no references pointi...
(COMPLETELY_ENTIRELY)
⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (2)
- GitHub Check: Agent
- GitHub Check: review
🔇 Additional comments (5)
README.md (1)
10-10: LGTM! Progress tracking accurately reflects the new Deep Clone problem.The updates correctly increment the problem counts across the GreatFrontEnd platform summary.
Also applies to: 46-46
greatfrontend/gfe-75/javascript-utilities/README.md (1)
12-12: LGTM! Deep Clone properly added to completed utilities.The entry follows the established format and correctly reflects the new implementation.
greatfrontend/gfe-75/javascript-utilities/deep-clone/README.md (1)
1-25: LGTM! Clear and comprehensive documentation.The documentation effectively explains the deep clone concept, provides practical examples, and sets clear expectations about the input constraints (JSON-serializable values only).
greatfrontend/gfe-75/javascript-utilities/deep-clone/deep-clone.ts (1)
1-11: LGTM! Clean and correct implementation.The implementation correctly handles all JSON-serializable types as specified in the requirements:
- Primitives and null (lines 2-4): Properly detected with
typeofand null check- Arrays (lines 5-7): Correctly identified with
Array.isArray()and recursively cloned- Objects (lines 8-10): Efficiently cloned using
Object.entriesandObject.fromEntriespattern with recursionThe function follows TypeScript best practices with explicit type annotations and leverages modern ES6+ features. The generic type parameter
Tprovides good type inference while theas Tassertions are necessary and safe given the control flow.Based on learnings, the public API is clear with a descriptive function name and straightforward parameter signature.
greatfrontend/gfe-75/README.md (1)
7-7: LGTM! Progress tracking and completed items accurately updated.The GFE 75 progress correctly reflects the new Deep Clone implementation, and the entry is properly placed under JavaScript Utilities with the correct difficulty level and path.
Also applies to: 16-16
📅 Spaced Repetition Reviews Scheduled!Great job solving #GFE-69c2 - Deep Clone! 🎉 To help you retain this knowledge long-term, I've scheduled 5 review sessions using spaced repetition:
What to expect:
🧠 Why Spaced Repetition?Research shows that reviewing material at increasing intervals dramatically improves retention. This adaptive scheduling ensures optimal spacing based on when you actually complete each review! Check |
Problem: #GFE-69c2 - Deep Clone PR: #103 First review scheduled (subsequent reviews auto-scheduled on completion) [skip ci]
Summary by CodeRabbit
New Features
Documentation
Tests
✏️ Tip: You can customize this high-level summary in your review settings.