files

📁 Files

A flexible filesystem API for Node and Bun:

import { read, walk } from "files";

// Find all of the readmes
const readmes = await walk("demo")
  .filter(/\/readme\.md$/) // Works as expected!
  .map(read);

console.log(readmes);
// ['# files', '# sub-dir', ...]

• Works with 'utf-8' by default.
• Supports Promises, WebStreams, NodeStreams (and Buffers and JSON).
• Extends promises with swear so you can chain operations easily.
• Absolute paths with the root as the running script.
• Ignores the second parameter if it's not an object so you can work with arrays better like .map(read).

It's an ideal library if you have to build scripts with many file and folder operations since it's made to simplify those.

function	description
abs()	retrieve the absolute path of the path
copy()	copy a file while keeping the original
dir()	get the directory of the path
exists()	check whenever a file or folder exists
home()	get the home directory
join()	put several path parts together in a cross-browser way
list()	list all of the files and folders of the path
mkdir()	create the specified directory
move()	copy a file while removing the original
name()	get the filename of the path
read()	read the file from the specified path
remove()	remove a file or folder (recursively)
rename()	alias of .move()
stat()	get some information about the current file
swear()	the promise wrapper that we use internally
tmp()	find the temporary directory or a folder inside
walk()	recursively list all of the files and folders
write()	create a new file or put data into a file

Swear package

All of the methods follow the swear promise extension. These are fully compatible with native promises:

// Using it as normal promises
const all = await list("demo");
const devFiles = all.filter((file) => !/node_modules/.test(file));
// ['a.js', 'b.js', ...]

With the swear workflow, you can apply operations on the promise that will be queued and run on the eventual value:

const devFiles = await list("demo").filter(
  (file) => !/node_modules/.test(file)
);
// ['a.js', 'b.js', ...]

See how we applied the .filter() straight into the output of list(). Then we have to await for the whole thing to resolve since list() is async. If this seems a bit confusing, read along the examples and try it yourself.

For convenience, you can import and use swear:

import files, { swear } from "files";

files.swear();
swear();

abs()

abs(path:string, root=process.cwd():string) => :string

Retrieve the absolute path of the passed argument relative of the directory running the script:

// cd ~/me/projects/files/ && node index.js

console.log(await abs("demo"));
// /home/me/projects/files/demo

console.log(await abs("../../Documents"));
// /home/me/Documents

It will return the same string if the path is already absolute.

You can pass a second parameter to specify any base directory different from the executing environment:

// cd ~/me/projects/files && node ./demo/abs.js ⚠️

// default; Relative to the place where the script is run
console.log(await abs("demo"));
// /home/me/projects/files/demo

// default; relative to the console location where the script is run
console.log(await abs("demo", process.cwd()));
// /home/me/projects/files/demo

// relative to the current directory (./demo)
console.log(await abs("demo", import.meta.url));
// /home/me/projects/files/demo/demo

If the second parameter is undefined, or if it's not a string, it will be completely ignored and the default of the current running dir will be used. This is great for looping on arrays or similar:

console.log(await list("demo").map(abs));
// [ '/home/me/projects/files/a', '/home/me/projects/files/b' ]

copy()

copy(source:string, destination:string) => :string

Copy the source file into the destination file, which can be in the same folder or in any other. It maintains the original. Returns the resulting file:

// cd ~/projects/files && node index.js

console.log(await copy("demo/README.md", "demo/readme.md"));
// /home/me/files/demo/readme.md

console.log(await copy("demo/readme.md", "demo/docs/readme.md"));
// /home/me/files/demo/docs/readme.md

Related methods:

• move(): copy a file while removing the original

dir()

dir(path:string) => :string

Returns the directory of the passed path:

console.log(await dir("~/hello/world.js"));
// /home/me/hello

If the path is already a directory, it returns the one that contains it; its parent:

console.log(await dir("~/hello/"));
// /home/me

exists()

exists(path:string) => :boolean

Check whenever a file or folder exists:

console.log(await exists("readme.md"));
// true

console.log(await exists("non-existing.md"));
// false

This cannot be used with .filter(), since in JS .filter() is sync and doesn't expect an array of promises to be returned.

To filter based on whether it exists or not, extend it to an array of promises, then filter that asynchronously and finally retrieve the original file:

const keeper = (file) => exists(file).then((keep) => keep && file);
const existing = await Promise.all(["a.md", "b.md"].map(keeper));
console.log(existing.filter((file) => file));

Swear interface: you can use swear to make your life a bit easier with its .filter(), which accepts promises:

import { swear } from "files";
console.log(await swear(["a.md", "b.md"]).filter(exists));

home()

home(arg1:string, arg2:string, ...) => :string

Find the home directory if called without arguments, or the specified directory inside the home folder as specified in the arguments.

console.log(await home());
// /home/me/

console.log(await home("demo"));
// /home/me/demo/

console.log(await home("demo", "a"));
// /home/me/demo/a/

It will create the specified folder if it does not exist yet.

To make sure the new folder is empty, you can call remove() and mkdir() consecutively:

const dir = await home("demo").then(remove).then(mkdir);
console.log(dir);
// /home/me/demo/ (empty)

join()

join(arg1:string, arg2:string, ...) => :string

Put several path segments together in a cross-browser way and return the absolute path:

console.log(await join("demo", "a"));
// /home/me/projects/files/demo/a

list()

list(path=process.cwd():string) => :Array(:string)

Get all of the files and folders of the specified directory into an array:

console.log(await list());
// ['/home/me/files/node_modules', '/home/me/files/demo/abs.js', ...]

To scan any other directory specify it as a parameter:

console.log(await list("demo"));
// ['/home/me/files/demo/a', '/home/me/files/demo/abs.js', ...]

Swear interface: you can iterate and treat the returned value as a normal array, except that you'll have to await at some point for the whole thing.

// Retrieve all of the files and filter for javascript
console.log(await list().filter(/\.js$/));
//  ['/home/me/projects/files/files.js', '/home/me/projects/files/files.test.js', ...]

Related methods:

• walk() recursively list all of the files in a directory. Does not output directories.

mkdir()

mkdir(path:string) => :string

Create the specified directory. If it already exists, do nothing. Returns the directory that was created.

// cd ~/projects/files && node index.js

console.log(await mkdir("demo/b"));
// /home/me/files/demo/b

Related methods:

• exists(): check whether a directory exists.
• remove(): remove a folder or file.
• list(): read all the contents of a directory.

move()

move(source:string, destination:string) => :string

Put the source file into the destination file. This can be just a rename or actually changing the folder where the file lives. Returns the resulting file:

// cd ~/projects/files && node index.js

console.log(await move("demo/README.md", "demo/readme.md"));
// /home/me/files/demo/readme.md

console.log(await move("demo/readme.md", "demo/docs/readme.md"));
// /home/me/files/demo/docs/readme.md

Related methods:

• copy(): copy a file while keeping the original

name()

name(path:string) => :string

Get the filename of the passed path:

console.log(await name("~/hello/world.js"));
// world.js

read()

read(path:string, { type: 'string' }) => :string

Read the specified file contents into a string:

console.log(await read("readme.md"));
// # files ...

console.log(await read("data.json").then(JSON.parse));
// { hello: "world" }

You can specify other types: raw, json, web (WebStream) and node (NodeStreams):

console.log(await read("data.json", { type: 'json' });
// { hello: "world" }

const stream = await read("data.json", { type: 'web' });
stream.pipeTo(...);

File reads are relative as always to the executing script. It expects a single argument so you can easily put an array on it:

// Read two files manually
console.log(await Promise.all(["a.md", "b.md"].map(read)));
// ['# A', '# B']

// Read all markdown files in all subfolders (using Swear interface):
console.log(await walk("demo").filter(/\.md$/).map(read));
// ['# A', '# B', ...]

It also follows the swear specification, so you can chain normal string operations on it:

// Find all the secondary headers in a markdown file
console.log(await read('readme.md').split('\n').filter(/^##\s+/));
// ['## abs()', '## dir()', ...]

// Read all markdown files in all subfolders
console.log(await walk().filter(/\.md$/).map(read)));
// ['# A', '# B', ...]

remove()

remove(path:string) => :string

Remove a file or folder (recursively) and return the absolute path that was removed

console.log(await remove("readme.md"));
// /home/me/projects/readme.md

console.log(await remove("~/old-project"));
// /home/me/old-project

Please be careful when using this, since there is no way of recovering deleted files.

rename()

alias of move().

stat()

stat(path:string) => :Object({
  isDirectory:fn,
  isFile:fn,
  atime:string,
  mtime:string,
  ...
})

Get some information about the current path:

console.log(await stat().isDirectory());
// true (the current directory)

console.log(await stat("readme.md").isFile());
// true

console.log(await stat("readme.md").atime);
// 2018-08-27T23:42:16.206Z

swear()

swear(arg:any) => :any

This is the swear package exported here for convenience. It allows you to chain promises using the underlying value methods for convenience.

Example: reading some specific files if they exist without swear:

const keeper = (file) => exists(file).then((keep) => keep && file);
const existing = await Promise.all(["a.md", "b.md"].map(keeper));
console.log(existing.filter(Boolean).map(read));

Reading the same files if they exist with swear:

console.log(await swear(["a.md", "b.md"]).filter(exists).map(read));

tmp()

tmp(arg1:string) => :string

Find the temporary directory. Find a subfolder if an argument is passed:

console.log(await tmp());
// /tmp/

console.log(await tmp("demo"));
// /tmp/demo/

console.log(await tmp("demo", "a"));
// /tmp/demo/a/

It will create the specified folder if it does not exist yet.

To reuse a temp folder and make sure it's empty on each usage, you can call remove() and mkdir() consecutively:

const dir = await tmp("demo").then(remove).then(mkdir);
console.log(dir);
// /tmp/demo/ (empty)

walk()

walk(path:string) => :Array(:string)

Recursively list all of the files from the specified folder:

// Retrieve all files inside './demo'
console.log(await walk("demo"));
// ['/home/me/projects/files/demo/readme.md', '/home/me/projects/files/demo/a/readme.md', ...]

It will not return directories. You can then use filter to filter e.g. by filename:

// Retrieve the content of all markdown files inside demo
console.log(
  await walk("demo")
    .filter((file) => /\.md$/.test(file))
    .map(read)
);
// ['# Readme A', '# Me also', ...]

write()

write(path:string, content:any) => :string

Create a new file or put data into a file that already exists. Returns the path of the file:

// Write to a file and then read its contents
console.log(await write("demo.txt", "Hello!").then(read));
// 'Hello!'

If the folder of the target file doesn't exist it will create it.

It accepts multiple types for the contect, specifically it accepts string, Buffer, ReadableStream (WebStreams) and Readable (NodeStreams) or a serializable object/array that will be converted to JSON.