feat: introduce alias option support

package.json

@@ -21,7 +21,7 @@
   ],
   "scripts": {
     "build": "unbuild",
-    "dev": "pnpm mkdist test/fixture -d",
+    "dev": "jiti src/cli test/fixture -d --alias={\\\"~\\\":\\\"\\\u0024\u005cSRC\\\"}",
     "lint": "eslint --ext .ts,.mjs,.cjs . && prettier --check src test",
     "lint:fix": "eslint --fix --ext .ts,.mjs,.cjs . && prettier --write -c src test",
     "mkdist": "jiti src/cli",

src/cli.ts

@@ -35,6 +35,10 @@ const main = defineCommand({
       description: "Pattern includes or excludes files",
       default: "**",
     },
+    alias: {
+      type: "string",
+      description: "Custom alias map used to resolve ids",
+    },
     format: {
       type: "string",
       description: "File format",
@@ -88,6 +92,7 @@ const main = defineCommand({
       distDir: args.dist,
       format: args.format,
       pattern: args.pattern,
+      alias: args.alias ? JSON.parse(args.alias) : undefined,
       ext: args.ext,
       declaration: args.declaration,
       loaders: args.loaders?.split(","),

src/make.ts

@@ -1,4 +1,13 @@
-import { resolve, extname, join, basename, dirname } from "pathe";
+import {
+  resolve,
+  extname,
+  join,
+  basename,
+  dirname,
+  relative,
+  parse,
+} from "pathe";
+import { resolveAlias } from "pathe/utils";
 import fse from "fs-extra";
 import { copyFileWithStream } from "./utils/fs";
 import {
@@ -20,6 +29,7 @@ export interface MkdistOptions extends LoaderOptions {
   cleanDist?: boolean;
   loaders?: (LoaderName | Loader)[];
   addRelativeDeclarationExtensions?: boolean;
+  alias?: { [find: string]: string };
 }
 
 export async function mkdist(
@@ -63,6 +73,70 @@ export async function mkdist(
     outputs.push(...((await loadFile(file)) || []));
   }
 
+  // Resolve aliases
+  if (options.alias && Object.keys(options.alias).length > 0) {
+    // Fast transform variables for alias
+    for (const [find, replace] of Object.entries(options.alias)) {
+      options.alias[find] = replace.replaceAll("$SRC", options.distDir);
+    }
+    const _resolveAlias = (
+      path: string,
+      aliases: Record<string, string>,
+      outputPath: OutputFile["path"] & string,
+    ) => {
+      // Resolve the alias and transform srcDir to distDir
+      const resolvedId = resolveAlias(path, aliases).replace(
+        options.srcDir,
+        options.distDir,
+      );
+
+      // if resolved path is in distDir, we transform it into a relative path
+      if (resolvedId.startsWith(options.distDir)) {
+        const from = parse(resolve(options.distDir, outputPath));
+        const to = parse(resolvedId);
+
+        // the OR `||` clause here means that the two files is in the same dir
+        const relativePath = relative(from.dir, join(to.dir, to.base));
+        // for cases like ('/index.ts, '/subfolder/index.ts'), `relative()` returns 'subfolder', without the leading './' which is incompatible with import/require path parameter
+        return relativePath.startsWith(".")
+          ? relativePath
+          : `./${relativePath}`;
+      }
+
+      return resolvedId;
+    };
+
+    for (const output of outputs.filter((o) => !o.raw)) {
+      output.contents = output.contents
+        // Resolve require statements
+        .replace(
+          /require\((["'])(.*)(["'])\)/g,
+          (_, head, id, tail) =>
+            "require(" +
+            head +
+            _resolveAlias(id, options.alias, output.path) +
+            tail +
+            ")",
+        )
+        // Resolve import statements
+        .replace(
+          /(import|export)(\s+(?:.+|{[\s\w,]+})\s+from\s+["'])(.*)(["'])/g,
+          (_, type, head, id, tail) =>
+            type + head + _resolveAlias(id, options.alias, output.path) + tail,
+        )
+        // Resolve dynamic import
+        .replace(
+          /import\((["'])(.*)(["'])\)/g,
+          (_, head, id, tail) =>
+            "import(" +
+            head +
+            _resolveAlias(id, options.alias, output.path) +
+            tail +
+            ")",
+        );
+    }
+  }
+
   // Normalize output extensions
   for (const output of outputs.filter((o) => o.extension)) {
     const renamed =

test/fixture/src/alias.ts

@@ -0,0 +1,12 @@
+import { foo2bar2 } from "~/nestedFolder/level2c";
+import { foo2 } from "~/nestedFolder/level2a";
+export { foo } from "~/nestedFolder/index";
+export const bar = () => import("~/nestedFolder").then((r) => r.bar);
+export const foo2bar = async () => {
+  const r = await bar();
+  return foo2 + r;
+};
+export const foo2baz2 = foo2bar2.replace("bar", "baz");
+
+// `require()` transform works but errors out because `mkdist` does not currently support mixed cjs and mjs building.
+// export const { baz } = require("~/nestedFolder/cjs")

test/fixture/src/nestedFolder/cjs.cjs

@@ -0,0 +1 @@
+module.exports = { baz: "baz" };

test/fixture/src/nestedFolder/index.ts

@@ -0,0 +1,2 @@
+export const foo = "foo";
+export const bar = "bar";

test/fixture/src/nestedFolder/level2a/index.ts

@@ -0,0 +1,3 @@
+import { foo } from "~/nestedFolder";
+
+export const foo2 = foo.repeat(2);

test/fixture/src/nestedFolder/level2b/index.ts

@@ -0,0 +1,3 @@
+import { bar } from "~/nestedFolder";
+
+export const bar2 = bar.repeat(2);

test/fixture/src/nestedFolder/level2c/index.ts

@@ -0,0 +1,4 @@
+import { foo2 } from "~/nestedFolder/level2a";
+import { bar2 } from "~/nestedFolder/level2b";
+
+export const foo2bar2 = foo2 + bar2;

test/fixture/tsconfig.json

@@ -0,0 +1,9 @@
+{
+  "compilerOptions": {
+    "baseUrl": ".",
+    "paths": {
+      "~/*": ["src/*"]
+    }
+  },
+  "include": ["src"]
+}

test/index.test.ts

@@ -29,12 +29,51 @@ describe("mkdist", () => {
         "dist/ts/test1.mjs",
         "dist/ts/test2.mjs",
         "dist/nested.css",
+        "dist/alias.mjs",
+        "dist/nestedFolder/cjs.mjs",
+        "dist/nestedFolder/index.mjs",
+        "dist/nestedFolder/level2a/index.mjs",
+        "dist/nestedFolder/level2b/index.mjs",
+        "dist/nestedFolder/level2c/index.mjs",
       ]
         .map((f) => resolve(rootDir, f))
         .sort(),
     );
   });
 
+  it("mkdist (resolve aliases)", async () => {
+    const rootDir = resolve(__dirname, "fixture");
+    const { writtenFiles } = await mkdist({
+      rootDir,
+      alias: { "~": resolve(rootDir, "src") },
+      pattern: ["alias.ts", "nestedFolder/**"],
+    });
+    expect(writtenFiles.sort()).containSubset(
+      [
+        "dist/alias.mjs",
+        "dist/nestedFolder/cjs.mjs",
+        "dist/nestedFolder/index.mjs",
+        "dist/nestedFolder/level2a/index.mjs",
+        "dist/nestedFolder/level2b/index.mjs",
+        "dist/nestedFolder/level2c/index.mjs",
+      ]
+        .map((f) => resolve(rootDir, f))
+        .sort(),
+    );
+
+    // Expect file to not contains any unresolved '`' alias
+    const indexFile = await readFile(
+      resolve(rootDir, "dist/alias.mjs"),
+      "utf8",
+    );
+    expect(indexFile).not.toMatch("~/");
+
+    // Expect the file to be able to execute normally
+    await import(resolve(rootDir, "dist/alias.mjs")).then(async (res) =>
+      expect(res.foo + (await res.bar())).toBe("foobar"),
+    );
+  });
+
   it("mkdist (custom glob pattern)", async () => {
     const rootDir = resolve(__dirname, "fixture");
     const { writtenFiles } = await mkdist({
@@ -113,6 +152,18 @@ describe("mkdist", () => {
         "dist/ts/test1.d.mts",
         "dist/ts/test2.d.cts",
         "dist/nested.css",
+        "dist/alias.mjs",
+        "dist/alias.d.ts",
+        "dist/nestedFolder/cjs.mjs",
+        "dist/nestedFolder/cjs.d.cts",
+        "dist/nestedFolder/index.mjs",
+        "dist/nestedFolder/level2a/index.mjs",
+        "dist/nestedFolder/level2b/index.mjs",
+        "dist/nestedFolder/level2c/index.mjs",
+        "dist/nestedFolder/index.d.ts",
+        "dist/nestedFolder/level2a/index.d.ts",
+        "dist/nestedFolder/level2b/index.d.ts",
+        "dist/nestedFolder/level2c/index.d.ts",
       ]
         .map((f) => resolve(rootDir, f))
         .sort(),
@@ -191,6 +242,12 @@ describe("mkdist", () => {
         "dist/ts/test1.mjs",
         "dist/ts/test2.mjs",
         "dist/nested.css",
+        "dist/alias.mjs",
+        "dist/nestedFolder/cjs.mjs",
+        "dist/nestedFolder/index.mjs",
+        "dist/nestedFolder/level2a/index.mjs",
+        "dist/nestedFolder/level2b/index.mjs",
+        "dist/nestedFolder/level2c/index.mjs",
       ]
         .map((f) => resolve(rootDir, f))
         .sort(),