Git Class Simulation

This repository contains a simple simulation of a Git version control system implemented in JavaScript. It provides basic functionalities such as committing changes, creating and checking out branches, and viewing commit history.

Classes

Commit

Represents a single commit in the repository.

Properties:
- id (Number): The unique identifier for the commit.
- parent (Commit | null): The parent commit.
- message (String): The commit message.

class Commit {
	constructor(id, parent, message) {
		this.id = id;
		this.parent = parent;
		this.message = message;
	}
}

Branch

Represents a branch in the repository.

Properties:
- name (String): The name of the branch.
- commit (Commit | null): The latest commit on the branch.

class Branch {
	constructor(name, commit) {
		this.name = name;
		this.commit = commit;
	}
}

Git

Represents the Git repository itself.

Properties:
- name (String): The name of the repository.
- lastCommitId (Number): The ID of the last commit made.
- branches (Array): A list of branches in the repository.
- HEAD (Branch): The currently active branch.
Methods:
- commit(message): Creates a new commit with the given message.
- checkout(branchName): Switches to the specified branch or creates a new one if it doesn't exist.
- log(): Returns the commit history of the current branch.

class Git {
	constructor(name) {
		this.name = name;
		this.lastCommitId = -1;
		this.branches = [];
		const master = new Branch('master', null);
		this.branches.push(master);
		this.HEAD = master;
	}

	commit(message) {
		const commit = new Commit(++this.lastCommitId, this.HEAD.commit, message);
		this.HEAD.commit = commit;
		return commit;
	}

	checkout(branchName) {
		for (let i = this.branches.length - 1; i >= 0; i--) {
			if (this.branches[i].name === branchName) {
				this.HEAD = this.branches[i];
				return this;
			}
		}
		const newBranch = new Branch(branchName, this.HEAD.commit);
		this.branches.push(newBranch);
		this.HEAD = newBranch;
		return this;
	}

	log() {
		let commit = this.HEAD.commit;
		const history = [];
		while (commit) {
			history.push(commit);
			commit = commit.parent;
		}
		return history;
	}
}

Usage Example

// Create a new Git repository
const repo = new Git('myrepo');

// Make an initial commit
repo.commit('Initial commit');

// Create and switch to a new branch 'newFeature'
repo.checkout('newFeature');

// Make a commit on the 'newFeature' branch
repo.commit('Added new feature');

// Retrieve and log the commit history
const history = repo.log();
console.log(history);

License

This project is licensed under the MIT License.