JSimportFMT

A high-performance CLI tool written in Go to automatically format and sort JavaScript and TypeScript imports by length. Optimized for very large repositories and CI/CD pipelines.

Command

➜  express-api git:(main) jsimportfmt ./router/apps.ts  --dry-run

Output

The output is all my imports are now formatted from shortest to longest.
Yes, Its a very niche tool and I just like my imports looking neet

--- ./router/apps.ts (original)
+++ ./router/apps.ts (formatted)
@@ -1,13 +1,13 @@
 import { Router } from "express";
-import { getTaxonomy } from "#/controllers/apps/taxonomy.Controller";
-import * as RfsController from "#/controllers/apps/rfs.Controller";
-import * as AppsController from "#/controllers/apps/apps.Controller";
-import * as ContributeController from "#/controllers/apps/contribute.Controller";
-import * as SubmitController from "#/controllers/apps/submit.Controller";
-import { authenticate } from "#/middleware/auth.middleware";
 import { UserRole } from "#/models/user.model";
+import { authenticate } from "#/middleware/auth.middleware";
 import { validate } from "#/middleware/validation.middleware";
 import * as ValidationSchema from "#/validation/apps.validation";
+import * as RfsController from "#/controllers/apps/rfs.Controller";
+import * as AppsController from "#/controllers/apps/apps.Controller";
+import { getTaxonomy } from "#/controllers/apps/taxonomy.Controller";
+import * as SubmitController from "#/controllers/apps/submit.Controller";
+import * as ContributeController from "#/controllers/apps/contribute.Controller";
 
 const router = Router();
 

✔ scanned 1 files

Features

• Blazing Fast: Written in Go using concurrent worker pools.
• Smart Parsing: Uses a lightweight state-machine parser instead of a slow AST, ensuring comments, spacing, and formatting within imports are perfectly preserved.
• Git & Gitignore Aware: Automatically respects .gitignore rules if a .git folder is found within 2 levels of the target.
• Non-Git Support: Works seamlessly in any directory, even without a Git repository.
• Type Separation: Built-in support to separate type imports (--separate-types).
• Interactive Mode: Launch a guided session by simply running jsimportfmt.
• Multiple Modes: Supports Write (--write), Check (--check), and Dry-Run (--dry-run) modes.

Installation

go install github.com/0necontroller/jsimportfmt@latest

Build Instructions

git clone https://github.com/0necontroller/jsimportfmt.git
cd jsimportfmt
go build -o jsimportfmt .

Usage Examples

Interactive Mode

Launch a guided session by running the command without arguments:

jsimportfmt

Format a Directory

Scan and rewrite all supported files in a folder:

jsimportfmt ./src --write

Format a Single File

Target a specific file directly:

jsimportfmt ./src/App.tsx --write

Dry-Run (Preview Changes)

See a unified diff of what would change without modifying any files:

jsimportfmt src --dry-run

Example Output:

--- src/index.ts (original)
+++ src/index.ts (formatted)
@@ -1,6 +1,6 @@
+import fs from "fs";
+import path from "path";
 import { App } from "./App";
 import { Config } from "./config";
-import path from "path";
-import fs from "fs";

Separate Type Imports

Sort regular imports and type imports into separate blocks:

jsimportfmt src --write --separate-types

Example: Before:

import type { User } from "./types";
import React from "react";
import type { Config } from "./config";
import { Button } from "./components";

After:

import React from "react";
import { Button } from "./components";

import type { User } from "./types";
import type { Config } from "./config";

Check Ignore Rules

List the default ignores and those parsed from .gitignore:

jsimportfmt . --check-ignore

Whitelist Directories

Allow formatting in ignored directories using a .jifallow file or the --allow flag.

Automatic Persistence: Using the --allow flag (e.g., --allow dist) will automatically append the directory to your .jifallow file if it's not already listed. If the file doesn't exist, it will be created with a helpful header comment.

jsimportfmt . --allow dist --allow build

The .jifallow file supports # comments and one directory per line. Any directory listed there (or passed via --allow) will bypass both default ignores and .gitignore rules.

See .jifallow.example for a concrete example.

Check Mode (CI)

Verify formatting without making changes:

jsimportfmt src --check

CI Usage

You can use jsimportfmt in your CI pipeline to enforce import formatting. Use the --check flag:

steps:
  - name: Check Import Formatting
    run: jsimportfmt . --check

Exit Codes

• 0: Success (no formatting needed, or all files successfully formatted in write mode)
• 1: Formatting needed (returned in --check mode)
• 2: Fatal error (e.g., file parsing failed or system error)

Performance Notes

jsimportfmt streams file discovery and feeds a worker pool matched to your system's CPU count (runtime.NumCPU()). It reads, parses, and formats files incrementally, ensuring low memory overhead even for monorepos with tens of thousands of files.