Modernizing SPFx Development: Transition to Heft in SPFx 1.22

Introduction

Microsoft has released SharePoint Framework (SPFx) 1.22, marking a significant modernization milestone for SharePoint and Microsoft 365 developers. This release introduces a new build and toolchain system that transitions from Gulp to a Webpack-based toolchain orchestrated by Heft, part of Microsoft’s RushStack ecosystem. This change aims to improve build performance, maintainability, and consistency with other Microsoft developer platforms such as Teams, Office Add-ins, and Viva Connections.

From Gulp to Heft: What Changed

Earlier Approach: Gulp-based Toolchain

In prior versions, SPFx relied heavily on Gulp for build orchestration. Developers managed tasks like:

• Compiling TypeScript
• Bundling with Webpack
• Packaging and serving the solution
• Running unit tests

Although powerful, this Gulp-based setup had limitations:

• Complex and manual task customization
• Dependency on older JavaScript build tools
• Difficult maintenance in large projects
• Slow build performance over time

New Approach: Heft-based Toolchain

SPFx 1.22 introduces a new, modern toolchain built on Heft - a flexible build orchestrator developed by Microsoft and part of the RushStack suite.

Heft coordinates the build using standardized configurations for Webpack, TypeScript, and other tools.

Key Components

• Heft - replaces Gulp as the main task runner
• Webpack 5 - modern bundler offering better optimization
• RushStack Libraries - provide a consistent foundation used across Microsoft projects
• Enhanced TypeScript Support - cleaner configuration and faster compilation

Benefits of the New Toolchain

Benefit	Description
Faster Builds	Webpack 5 and Heft caching reduce build and serve times.
Unified Ecosystem	Aligns SPFx with other Microsoft frameworks using RushStack.
Simplified Customization	Developers can use Heft plugins or configuration files instead of custom Gulp scripts.
Modern Web Standards	Supports ES Modules, efficient tree-shaking, and advanced optimizations.
Future-readiness	Prepares SPFx for future scalability and integration improvements.

How Developers Can Prepare for This Transition?

Transitioning from Gulp to Heft requires some adaptation in the way SPFx developers handle builds and configuration.
Here’s how to prepare effectively:

1. Understand the RushStack Ecosystem

Spend time learning the RushStack ecosystem:

• Heft Overview
• Rush for Monorepos
• Rig Packages and Plugin Architecture

These concepts form the foundation of the new SPFx build process.

2. Update Node.js and NPM

Ensure your environment uses compatible versions:

• Node.js 18.x or later
• NPM 9.x or later

Older versions may cause dependency or script compatibility issues.

3. Review Custom Gulp Tasks

If your solution uses custom Gulp tasks (e.g., for file copying or code generation), you’ll need to:

• Identify each custom task.
• Determine if there’s an equivalent Heft plugin or hook.
• Move logic into a Heft-compatible plugin or event hook.

4. Learn Webpack 5 Enhancements

Heft uses Webpack 5, so understanding key Webpack concepts like module federation, asset modules, and configuration overrides will help optimize your builds.

5. Explore Heft Config Files

Heft relies on configuration files like heft.json and tsconfig.json to define tasks. Learn their structure and how they replace legacy Gulp settings.

Guidelines for Upgrading Existing Projects

Here are practical steps to migrate your SPFx solutions from older versions to the new Heft-based toolchain:

• Backup your project - always keep a working copy of your Gulp-based solution.
• Upgrade SPFx version using:
• npm install @microsoft/sp-build-web@1.22
• Run project upgrade command:
• gulp upgrade

(Note: this command will update configurations, but may not fully remove Gulp dependencies.)

• Review the new project structure:
  • Verify the presence of config/heft.json and related RushStack files.
  • Check for deprecations in gulpfile.js (many will now be unused).
• Clean up obsolete Gulp references:
  • Remove unnecessary gulp-* packages.
  • Update build scripts in package.json to use Heft commands.
• Test builds:
  • npm run build
  • npm run serve
  • npm run package-solution
• Resolve compatibility issues:
  • Update third-party libraries (especially React, TypeScript).
  • Check for breaking changes in your custom tasks.

Learning Curve and Developer Readiness

While the transition introduces modern practices, developers may face a learning curve, especially if they have relied on Gulp for years.

Here is what to expect:

Area	Tip
Heft Orchestration	Start with Microsoft’s Heft documentation.
Webpack 5 Features	Experiment with small sample projects to learn bundling concepts.
Configuration Files	Understand JSON-based configurations rather than Gulp tasks.
Debugging	Use Heft logs and Webpack Dev Server for troubleshooting.

Overall, developers familiar with modern JavaScript toolchains (like Webpack or Vite) will find the transition smoother. For others, short learning sessions and experimentation will help adapt quickly.

Use Cases

• Enterprise SPFx Solutions - Faster builds and better modularization in large-scale environments.
• Teams and Viva Integrations - Shared toolchain consistency between Microsoft 365 workloads.
• DevOps Automation - Easier integration into CI/CD systems with standardized Heft commands.

Summary

SPFx 1.22 introduces a modernized, Heft-based toolchain that replaces legacy Gulp tasks, streamlining development with improved performance, maintainability, and extensibility.
While the transition requires developers to adapt to new tools like Heft and Webpack 5, it sets a strong foundation for the future of SPFx and Microsoft 365 development.

By preparing early, reviewing existing projects, and embracing modern JavaScript practices, developers can make this transition smooth and take full advantage of what SPFx 1.22 offers.

References

• SPFx 1.22 Release Notes - Microsoft Learn
• SPFx Toolchain: Transitioning to Heft - Microsoft Learn
• RushStack Official Site
• Heft Overview