feat: support lib.id

packages/core/src/cli/commands.ts

@@ -52,7 +52,7 @@ export function runCli(): void {
 
   buildCommand
     .option(
-      '--lib <name>',
+      '--lib <id>',
       'build the specified library (may be repeated)',
       repeatableOption,
     )
@@ -75,7 +75,7 @@ export function runCli(): void {
   inspectCommand
     .description('inspect the Rsbuild / Rspack configs of Rslib projects')
     .option(
-      '--lib <name>',
+      '--lib <id>',
       'inspect the specified library (may be repeated)',
       repeatableOption,
     )

packages/core/src/config.ts

@@ -33,12 +33,14 @@ import type {
   AutoExternal,
   BannerAndFooter,
   DeepRequired,
+  ExcludesFalse,
   Format,
   LibConfig,
   LibOnlyConfig,
   PkgJson,
   Redirect,
   RsbuildConfigOutputTarget,
+  RsbuildConfigWithLibInfo,
   RslibConfig,
   RslibConfigAsyncFn,
   RslibConfigExport,
@@ -1182,7 +1184,7 @@ async function composeLibRsbuildConfig(config: LibConfig, configPath: string) {
 export async function composeCreateRsbuildConfig(
   rslibConfig: RslibConfig,
   path?: string,
-): Promise<{ format: Format; config: RsbuildConfig }[]> {
+): Promise<RsbuildConfigWithLibInfo[]> {
   const constantRsbuildConfig = await createConstantRsbuildConfig();
   const configPath = path ?? rslibConfig._privateMeta?.configFilePath!;
   const { lib: libConfigsArray, ...sharedRsbuildConfig } = rslibConfig;
@@ -1216,7 +1218,7 @@ export async function composeCreateRsbuildConfig(
     userConfig.output ??= {};
     delete userConfig.output.externals;
 
-    return {
+    const config: RsbuildConfigWithLibInfo = {
       format: libConfig.format!,
       // The merge order represents the priority of the configuration
       // The priorities from high to low are as follows:
@@ -1230,6 +1232,7 @@ export async function composeCreateRsbuildConfig(
         constantRsbuildConfig,
         libRsbuildConfig,
         omit<LibConfig, keyof LibOnlyConfig>(userConfig, {
+          id: true,
           bundle: true,
           format: true,
           autoExtension: true,
@@ -1245,6 +1248,12 @@ export async function composeCreateRsbuildConfig(
         }),
       ),
     };
+
+    if (typeof libConfig.id === 'string') {
+      config.id = libConfig.id;
+    }
+
+    return config;
   });
 
   const composedRsbuildConfig = await Promise.all(libConfigPromises);
@@ -1253,31 +1262,52 @@ export async function composeCreateRsbuildConfig(
 
 export async function composeRsbuildEnvironments(
   rslibConfig: RslibConfig,
+  path?: string,
 ): Promise<Record<string, EnvironmentConfig>> {
-  const rsbuildConfigObject = await composeCreateRsbuildConfig(rslibConfig);
+  const rsbuildConfigWithLibInfo = await composeCreateRsbuildConfig(
+    rslibConfig,
+    path,
+  );
+
+  // User provided ids should take precedence over generated ids.
+  const usedIds = rsbuildConfigWithLibInfo
+    .map(({ id }) => id)
+    .filter(Boolean as any as ExcludesFalse);
   const environments: RsbuildConfig['environments'] = {};
-  const formatCount: Record<Format, number> = rsbuildConfigObject.reduce(
+  const formatCount: Record<Format, number> = rsbuildConfigWithLibInfo.reduce(
     (acc, { format }) => {
       acc[format] = (acc[format] ?? 0) + 1;
       return acc;
     },
     {} as Record<Format, number>,
   );
 
-  const formatIndex: Record<Format, number> = {
-    esm: 0,
-    cjs: 0,
-    umd: 0,
-    mf: 0,
+  const composeDefaultId = (format: Format): string => {
+    const nextDefaultId = (format: Format, index: number) => {
+      return `${format}${formatCount[format] === 1 && index === 0 ? '' : index}`;
+    };
+
+    let index = 0;
+    let candidateId = nextDefaultId(format, index);
+    while (usedIds.indexOf(candidateId) !== -1) {
+      candidateId = nextDefaultId(format, ++index);
+    }
+    usedIds.push(candidateId);
+    return candidateId;
   };
 
-  for (const { format, config } of rsbuildConfigObject) {
-    const currentFormatCount = formatCount[format];
-    const currentFormatIndex = formatIndex[format]++;
+  for (const { format, id, config } of rsbuildConfigWithLibInfo) {
+    const libId = typeof id === 'string' ? id : composeDefaultId(format);
+    environments[libId] = config;
+  }
 
-    environments[
-      currentFormatCount === 1 ? format : `${format}${currentFormatIndex}`
-    ] = config;
+  const conflictIds = usedIds.filter(
+    (id, index) => usedIds.indexOf(id) !== index,
+  );
+  if (conflictIds.length) {
+    throw new Error(
+      `The following ids are duplicated: ${conflictIds.map((id) => `"${id}"`).join(', ')}. Please change the "lib.id" to be unique.`,
+    );
   }
 
   return environments;

packages/core/src/types/config/index.ts

@@ -18,6 +18,12 @@ export type FixedEcmaVersions =
 export type LatestEcmaVersions = 'es2024' | 'esnext';
 export type EcmaScriptVersion = FixedEcmaVersions | LatestEcmaVersions;
 
+export type RsbuildConfigWithLibInfo = {
+  id?: string;
+  format: Format;
+  config: RsbuildConfig;
+};
+
 export type RsbuildConfigOutputTarget = NonNullable<
   RsbuildConfig['output']
 >['target'];
@@ -72,6 +78,11 @@ export type Redirect = {
 };
 
 export interface LibConfig extends RsbuildConfig {
+  /**
+   * The unique identifier of the library.
+   * @default undefined
+   */
+  id?: string;
   /**
    * Output format for the generated JavaScript files.
    * @default undefined

packages/core/src/types/utils.ts

@@ -10,3 +10,5 @@ export type PkgJson = {
 export type DeepRequired<T> = Required<{
   [K in keyof T]: T[K] extends Required<T[K]> ? T[K] : DeepRequired<T[K]>;
 }>;
+
+export type ExcludesFalse = <T>(x: T | false | undefined | null) => x is T;

packages/core/tests/config.test.ts

@@ -1,6 +1,10 @@
 import { join } from 'node:path';
 import { describe, expect, test, vi } from 'vitest';
-import { composeCreateRsbuildConfig, loadConfig } from '../src/config';
+import {
+  composeCreateRsbuildConfig,
+  composeRsbuildEnvironments,
+  loadConfig,
+} from '../src/config';
 import type { RslibConfig } from '../src/types/config';
 
 vi.mock('rslog');
@@ -402,3 +406,117 @@ describe('minify', () => {
     `);
   });
 });
+
+describe('id', () => {
+  test('default id logic', async () => {
+    const rslibConfig: RslibConfig = {
+      lib: [
+        {
+          format: 'esm',
+        },
+        {
+          format: 'cjs',
+        },
+        {
+          format: 'esm',
+        },
+        {
+          format: 'umd',
+        },
+        {
+          format: 'esm',
+        },
+      ],
+    };
+
+    const composedRsbuildConfig = await composeRsbuildEnvironments(
+      rslibConfig,
+      process.cwd(),
+    );
+
+    expect(Object.keys(composedRsbuildConfig)).toMatchInlineSnapshot(`
+      [
+        "esm0",
+        "cjs",
+        "esm1",
+        "umd",
+        "esm2",
+      ]
+    `);
+  });
+
+  test('with user specified id', async () => {
+    const rslibConfig: RslibConfig = {
+      lib: [
+        {
+          id: 'esm1',
+          format: 'esm',
+        },
+        {
+          format: 'cjs',
+        },
+        {
+          format: 'esm',
+        },
+        {
+          id: 'cjs',
+          format: 'umd',
+        },
+        {
+          id: 'esm0',
+          format: 'esm',
+        },
+      ],
+    };
+
+    const composedRsbuildConfig = await composeRsbuildEnvironments(
+      rslibConfig,
+      process.cwd(),
+    );
+    expect(Object.keys(composedRsbuildConfig)).toMatchInlineSnapshot(`
+      [
+        "esm1",
+        "cjs1",
+        "esm2",
+        "cjs",
+        "esm0",
+      ]
+    `);
+  });
+
+  test('do not allow conflicted id', async () => {
+    const rslibConfig: RslibConfig = {
+      lib: [
+        {
+          id: 'a',
+          format: 'esm',
+        },
+        {
+          format: 'cjs',
+        },
+        {
+          format: 'esm',
+        },
+        {
+          id: 'a',
+          format: 'umd',
+        },
+        {
+          id: 'b',
+          format: 'esm',
+        },
+        {
+          id: 'b',
+          format: 'esm',
+        },
+      ],
+    };
+
+    // await composeRsbuildEnvironments(rslibConfig, process.cwd());
+    await expect(() =>
+      composeRsbuildEnvironments(rslibConfig, process.cwd()),
+    ).rejects.toThrowError(
+      'The following ids are duplicated: "a", "b". Please change the "lib.id" to be unique.',
+    );
+  });
+});

website/docs/en/config/lib/_meta.json

@@ -10,5 +10,6 @@
   "footer",
   "dts",
   "shims",
+  "id",
   "umd-name"
 ]

website/docs/en/config/lib/id.mdx

@@ -0,0 +1,60 @@
+# lib.id
+
+- **Type:** `string`
+- **Default:** `undefined`
+
+Specify the library ID. The ID identifies the library and is useful when using the `--lib` flag to build specific libraries with a meaningful `id` in the CLI.
+
+:::tip
+
+Rslib uses Rsbuild's [environments](https://rsbuild.dev/guide/advanced/environments) feature to build multiple libraries in a single project under the hood. `lib.id` will be used as the key for the generated Rsbuild environment.
+
+:::
+
+## Default Value
+
+By default, Rslib automatically generates an ID for each library in the format `${format}${index}`. Here, `format` refers to the value specified in the current lib's [format](/config/lib/format), and `index` indicates the order of the library within all libraries of the same format. If there is only one library with the current format, the `index` will be empty. Otherwise, it will start from `0` and increment.
+
+For example, the libraries in the `esm` format will start from `esm0`, followed by `esm1`, `esm2`, and so on. In contrast, `cjs` and `umd` formats do not include the `index` part since there is only one library for each format.
+
+```ts title="rslib.config.ts"
+export default {
+  lib: [
+    { format: 'esm' }, // id is `esm0`
+    { format: 'cjs' }, // id is `cjs`
+    { format: 'esm' }, // id is `esm1`
+    { format: 'umd' }, // id is `umd`
+    { format: 'esm' }, // id is `esm2`
+  ],
+};
+```
+
+## Customize ID
+
+You can also specify a readable or meaningful ID of the library by setting the `id` field in the library configuration. The user-specified ID will take priority, while the rest will be used together to generate the default ID.
+
+For example, `my-lib-a`, `my-lib-b`, and `my-lib-c` will be the IDs of the specified libraries, while the rest will be used to generate and apply the default ID.
+
+{/* prettier-ignore-start */}
+```ts title="rslib.config.ts"
+export default {
+  lib: [
+    { format: 'esm', id: 'my-lib-a' }, // ID is `my-lib-a`
+    { format: 'cjs', id: 'my-lib-b' }, // ID is `my-lib-b`
+    { format: 'esm' },                 // ID is `esm0`
+    { format: 'umd', id: 'my-lib-c' }, // ID is `my-lib-c`
+    { format: 'esm' },                 // ID is `esm1`
+  ],
+};
+```
+{/* prettier-ignore-end */}
+
+Then you could only build `my-lib-a` and `my-lib-b` by running the following command:
+
+```bash
+npx rslib build --lib my-lib-a --lib my-lib-b
+```
+
+:::note
+The id of each library must be unique, otherwise it will cause an error.
+:::