Implement a simple in-memory filesystem library in JavaScript that supports the following functionalities.
- createDirectory(name) – Creates a new directory at the current path.
- changeDirectory(path) – Changes the directory path.
- addFile(name) – Adds a new file at the current path.
- deleteFile(name) – Deletes the file with given name at the current path.
- deleteDirectory(name) – Deletes the directory with given name at the given path.
- getRootDirectory – Returns the root directory and all its nested childs.
- getCurDirectory – Returns the items of current directory.
- getCurDirectoryPath – Returns the path of the current directory.
To implement this function we will be extensively using Objects, working with objects is a complex task especially if you are not thoroughly aware of how objects as a reference can be used effectively.
Boilerplate.
const FileSystem = function(){ this.directory = {"root": {}}; this.currentDir = this.directory["root"]; this.currentDirPath = "root"; }; Here we have defined 3 variables,
- directory – Holds the root directory.
- currentDir – Holds the reference to the root directory.
- currentDirPath – Holds the path of the current directory.
Create a new directory
A new directory is just a new object added to the given path.
this.createDirectory = function(name){ this.currentDir[name] = {}; } Change path of the directory
We accept the directory path as an absolute value separated by hyphen path-subpath-subpath. Once the directory changes, we also update the currentDir object reference. This way when you create a new directory or add a new file it will be added to the currentDir only.
Note – we are not checking if the directory exists or not.
this.changeDirectory = function(path) { this.currentDir = this._changeDirectoryHelper(path); this.currentDirPath = path; } this._changeDirectoryHelper = function(path) { const paths = path.split("-"); let current = this.directory; for(let key of paths){ current = current[key]; } return current; } Get current directory.
Returns the current directory object.
this.getCurDirectoryPath = function(){ return this.currentDirPath; } Get current directory path.
this.getCurDirectory = function(){ return this.currentDir; } Add file
At the current path the files will be added to the key “files” as an array making it easy to add and remove them.
this.addFile = function(fileName){ if(this.currentDir.files){ this.currentDir.files.push(fileName); }else{ this.currentDir["files"] = [fileName]; } return true; } Remove file
To remove files simply filter the files array at the current directory.
this.deleteFile = function(fileName){ this.currentDir.files = this.currentDir.files.filter((e) => e !== fileName); return true; } Delete the directory
To delete the directory, change to the current path and delete any of the sub-directory.
this.deleteDirectory = function(name){ delete this.currentDir[name]; } Get the root directory
Returns the root object.
this.getRootDirectory = function(){ return this.directory; } Complete code
const FileSystem = function(){ this.directory = {"root": {}}; this.currentDir = this.directory["root"]; this.currentDirPath = "root"; this.createDirectory = function(name){ this.currentDir[name] = {}; } this.changeDirectory = function(path) { this.currentDir = this._changeDirectoryHelper(path); this.currentDirPath = path; } this._changeDirectoryHelper = function(path) { const paths = path.split("-"); let current = this.directory; for(let key of paths){ current = current[key]; } return current; } this.getCurDirectoryPath = function(){ return this.currentDirPath; } this.getCurDirectory = function(){ return this.currentDir; } this.addFile = function(fileName){ if(this.currentDir.files){ this.currentDir.files.push(fileName); }else{ this.currentDir["files"] = [fileName]; } return true; } this.deleteFile = function(fileName){ this.currentDir.files = this.currentDir.files.filter((e) => e !== fileName); return true; } this.deleteDirectory = function(name){ delete this.currentDir[name]; } this.getRootDirectory = function(){ return this.directory; } } Input: const dir = new FileSystem(); dir.createDirectory('prashant'); dir.changeDirectory('root-prashant'); dir.addFile('index.html'); dir.addFile('app.js'); dir.changeDirectory('root'); dir.createDirectory('practice'); dir.changeDirectory('root-practice'); dir.addFile('index.html'); dir.addFile('app.js'); dir.createDirectory('build'); dir.changeDirectory('root-practice-build'); dir.addFile('a.png'); dir.addFile('b.jpg'); dir.deleteFile('a.png'); dir.changeDirectory('root'); dir.deleteDirectory('prashant'); console.log(dir.getRootDirectory()); Output: { "root": { "practice": { "files": [ "index.html", "app.js" ], "build": { "files": [ "b.jpg" ] } } } } Not as we are using the object as a reference and making the updates on it, printing the directory and performing action after that will still show the updated object.