feat!: add JavaScript API and enhance CLI behaviour

[Timeless0911]

Highlights 💡

New JavaScript API

This release introduces a new, comprehensive JavaScript API for Rslib.

Caution

This is a Breaking Change. The previously exposed informal API has been removed. You can switch to the new JavaScript API and refer to the docs below to re-integrate.

See the API docs for details:

• Rslib core methods
• Rslib instance
• Rslib types

Usage

1. Install Rslib: install the @rslib/core package:

npm add @rslib/core -D

2. Create an Rslib instance: call the createRslib method to create an Rslib instance:

import { createRslib } from '@rslib/core';

const rslib = await createRslib();

3. Call Rslib instance methods: use the rslib.build method which will build production outputs:

await rslib.build();

Summary

• Provide a comprehensive JavaScript API

  Type:

   type RslibInstance = {
       build(options?: BuildOptions): Promise<BuildResult>;
       inspectConfig(options?: InspectConfigOptions): Promise<InspectConfigResult>;
       startMFDevServer(options?: StartMFDevServerOptions): Promise<StartServerResult>;
       getRslibConfig(): Readonly<RslibConfig>;
       onAfterCreateRsbuild(callback: OnAfterCreateRsbuildFn): void;
   };
   
   function createRslib(options?: CreateRslibOptions): Promise<RslibInstance>;

  Example:

   const rslib = await createRslib({
     config: {
       // Rslib configuration
     },
   });
  
   await rslib.build();

• Refactor public API

  Core methods:

  • runCLI
  • createRslib
  • defineConfig
  • loadConfig
  • loadEnv
  • mergeRslibConfig

• Verbose Rslib/Rsbuild/Rspack configurations when running with DEBUG=rslib

• Add --no-env cli options to control disable loading of .env files after refactor

Related Links

close: #1040
close: #967

Checklist

• PR Description
• Tests updated (or not required).
• JS Doc
• Documentation updated (or not required).
• Breaking changes and release notes

[Copilot]

Pull request overview

This PR refactors the CLI initialization and error handling to improve user experience. The main changes include renaming the public API from runCli to runCLI (following proper casing convention), consolidating CLI setup logic, and implementing smarter output formatting for different package managers. The refactor also adds a process title for easier identification and simplifies build error logging.

Key changes:

• Renamed public API runCli to runCLI and consolidated CLI initialization logic into a new /cli/index.ts file
• Removed the prepareCli function and integrated its functionality into the main CLI entry point
• Enhanced package manager detection to handle output formatting for npx, Bun, and Node.js --run command
• Introduced RSPACK_BUILD_ERROR constant to conditionally suppress redundant error messages
• Renamed internal function initConfig to init for better clarity

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
packages/core/src/index.ts	Updated public API exports: renamed runCli to runCLI and removed prepareCli export
packages/core/src/cli/prepare.ts	Deleted file - functionality moved to /cli/index.ts
packages/core/src/cli/init.ts	Renamed function from initConfig to init
packages/core/src/cli/index.ts	New file consolidating CLI initialization with improved package manager detection and greeting logic
packages/core/src/cli/commands.ts	Added RSPACK_BUILD_ERROR constant and error filtering logic; renamed import from initConfig to init; updated import path
packages/core/bin/rslib.js	Simplified entry point to call runCLI directly without try-catch wrapper

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