feat: support tsconfig-paths

Author: hanayashiki

loader.mjs

@@ -1,12 +1,20 @@
 import { URL, pathToFileURL, fileURLToPath } from 'url'
 import fs from 'fs'
 import { transformSync } from 'esbuild'
+import { createMatchPath, loadConfig } from 'tsconfig-paths'
 
 const baseURL = pathToFileURL(`${process.cwd()}/`).href
 const isWindows = process.platform === 'win32'
 
-const extensionsRegex = /\.(tsx?|json)$/
+const extensionsRegex = /\.(m?tsx?|json)$/
 const excludeRegex = /^\w+:/
+const tsExtensions = ['.ts', '.mts', '.cts', '.tsx'] // https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-5.html
+const jsExtensions = ['.js', '.cjs', '.mjs', '.jsx']
+const extensions = [...tsExtensions, ...jsExtensions]
+
+const tsconfig = loadConfig()
+
+const matchPath = tsconfig.resultType === 'success' ? createMatchPath(tsconfig.absoluteBaseUrl, tsconfig.paths) : undefined
 
 function esbuildTransformSync(rawSource, filename, url, format) {
   const {
@@ -31,7 +39,29 @@ function esbuildTransformSync(rawSource, filename, url, format) {
   return { js, jsSourceMap }
 }
 
+export const tryPathWithExtensions = (path) => {
+  for (const ext of extensions) {
+    const p = `${path}${ext}`
+    if (fs.existsSync(p))
+      return p
+  }
+  return null
+}
+
 export function resolve(specifier, context, defaultResolve) {
+  // baseUrl & paths takes the highest precedence, as TypeScript behaves.
+  if (matchPath) {
+    const nodePath = matchPath(specifier, undefined, undefined, extensions)
+
+    if (nodePath) {
+      const foundPath = tryPathWithExtensions(nodePath)
+      return {
+        url: pathToFileURL(foundPath).href,
+        format: extensionsRegex.test(foundPath) && 'module',
+      }
+    }
+  }
+
   const { parentURL = baseURL } = context
   const url = new URL(specifier, parentURL)
   if (extensionsRegex.test(url.pathname))
@@ -40,15 +70,14 @@ export function resolve(specifier, context, defaultResolve) {
   // ignore `data:` and `node:` prefix etc.
   if (!excludeRegex.test(specifier)) {
     // Try to resolve extension
-    const pathname = url.pathname
-    for (const ext of ['ts', 'tsx']) {
-      url.pathname = `${pathname}.${ext}`
-      const path = fileURLToPath(url.href)
-      if (fs.existsSync(path))
-        return {
-          url: url.href,
-          format: extensionsRegex.test(url.pathname) && 'module',
-        }
+    const path = fileURLToPath(url.href)
+    const foundPath = tryPathWithExtensions(path)
+    if (foundPath) {
+      url.pathname = foundPath
+      return {
+        url: url.href,
+        format: extensionsRegex.test(url.pathname) && 'module',
+      }
     }
   }
 

package.json

@@ -33,7 +33,8 @@
     "test": "node --experimental-loader ./loader.mjs test/entry.ts"
   },
   "dependencies": {
-    "esbuild": "^0.13.3"
+    "esbuild": "^0.13.3",
+    "tsconfig-paths": "^3.11.0"
   },
   "devDependencies": {
     "@antfu/eslint-config": "^0.9.0",

pnpm-lock.yaml

@@ -107,4 +107,15 @@ test('import json', async() => {
   assert(stdout === 'esbuild-node-loader')
 })
 
+test('tsconfig-paths', async() => {
+  const { stdout } = await execa('node', [
+    '--experimental-loader',
+    `${cwd}/loader.mjs`,
+    `${cwd}/test/tsconfig-paths/src/utils/fixture.ts`,
+  ], {
+    cwd: `${cwd}/test/tsconfig-paths`,
+  })
+  assert.equal(stdout, 'foo\nfoo')
+})
+
 test.run()

test/entry.ts

@@ -0,0 +1,3 @@
+export const foo = () => {
+  console.info('foo')
+}

test/tsconfig-paths/node_modules/@apis/foo.ts

@@ -0,0 +1,3 @@
+export const index = () => {
+  console.info('index')
+}

test/tsconfig-paths/src/apis/foo.ts

@@ -0,0 +1,5 @@
+import { foo as foo2 } from 'src/apis/foo'
+import { foo } from '@apis/foo'
+
+foo()
+foo2()

test/tsconfig-paths/src/apis/index.ts

@@ -0,0 +1,106 @@
+{
+  "compilerOptions": {
+    /* Visit https://aka.ms/tsconfig.json to read more about this file */
+
+    /* Projects */
+    // "incremental": true,                              /* Enable incremental compilation */
+    // "composite": true,                                /* Enable constraints that allow a TypeScript project to be used with project references. */
+    // "tsBuildInfoFile": "./",                          /* Specify the folder for .tsbuildinfo incremental compilation files. */
+    // "disableSourceOfProjectReferenceRedirect": true,  /* Disable preferring source files instead of declaration files when referencing composite projects */
+    // "disableSolutionSearching": true,                 /* Opt a project out of multi-project reference checking when editing. */
+    // "disableReferencedProjectLoad": true,             /* Reduce the number of projects loaded automatically by TypeScript. */
+
+    /* Language and Environment */
+    "target": "es5",                                     /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */
+    // "lib": [],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */
+    // "jsx": "preserve",                                /* Specify what JSX code is generated. */
+    // "experimentalDecorators": true,                   /* Enable experimental support for TC39 stage 2 draft decorators. */
+    // "emitDecoratorMetadata": true,                    /* Emit design-type metadata for decorated declarations in source files. */
+    // "jsxFactory": "",                                 /* Specify the JSX factory function used when targeting React JSX emit, e.g. 'React.createElement' or 'h' */
+    // "jsxFragmentFactory": "",                         /* Specify the JSX Fragment reference used for fragments when targeting React JSX emit e.g. 'React.Fragment' or 'Fragment'. */
+    // "jsxImportSource": "",                            /* Specify module specifier used to import the JSX factory functions when using `jsx: react-jsx*`.` */
+    // "reactNamespace": "",                             /* Specify the object invoked for `createElement`. This only applies when targeting `react` JSX emit. */
+    // "noLib": true,                                    /* Disable including any library files, including the default lib.d.ts. */
+    // "useDefineForClassFields": true,                  /* Emit ECMAScript-standard-compliant class fields. */
+
+    /* Modules */
+    "module": "commonjs",                                /* Specify what module code is generated. */
+    // "rootDir": "./",                                  /* Specify the root folder within your source files. */
+    // "moduleResolution": "node",                       /* Specify how TypeScript looks up a file from a given module specifier. */
+    // "baseUrl": "./",                                  /* Specify the base directory to resolve non-relative module names. */
+    // "paths": {},                                      /* Specify a set of entries that re-map imports to additional lookup locations. */
+    // "rootDirs": [],                                   /* Allow multiple folders to be treated as one when resolving modules. */
+    // "typeRoots": [],                                  /* Specify multiple folders that act like `./node_modules/@types`. */
+    // "types": [],                                      /* Specify type package names to be included without being referenced in a source file. */
+    // "allowUmdGlobalAccess": true,                     /* Allow accessing UMD globals from modules. */
+    // "resolveJsonModule": true,                        /* Enable importing .json files */
+    // "noResolve": true,                                /* Disallow `import`s, `require`s or `<reference>`s from expanding the number of files TypeScript should add to a project. */
+
+    /* JavaScript Support */
+    // "allowJs": true,                                  /* Allow JavaScript files to be a part of your program. Use the `checkJS` option to get errors from these files. */
+    // "checkJs": true,                                  /* Enable error reporting in type-checked JavaScript files. */
+    // "maxNodeModuleJsDepth": 1,                        /* Specify the maximum folder depth used for checking JavaScript files from `node_modules`. Only applicable with `allowJs`. */
+
+    /* Emit */
+    // "declaration": true,                              /* Generate .d.ts files from TypeScript and JavaScript files in your project. */
+    // "declarationMap": true,                           /* Create sourcemaps for d.ts files. */
+    // "emitDeclarationOnly": true,                      /* Only output d.ts files and not JavaScript files. */
+    // "sourceMap": true,                                /* Create source map files for emitted JavaScript files. */
+    // "outFile": "./",                                  /* Specify a file that bundles all outputs into one JavaScript file. If `declaration` is true, also designates a file that bundles all .d.ts output. */
+    // "outDir": "./",                                   /* Specify an output folder for all emitted files. */
+    // "removeComments": true,                           /* Disable emitting comments. */
+    // "noEmit": true,                                   /* Disable emitting files from a compilation. */
+    // "importHelpers": true,                            /* Allow importing helper functions from tslib once per project, instead of including them per-file. */
+    // "importsNotUsedAsValues": "remove",               /* Specify emit/checking behavior for imports that are only used for types */
+    // "downlevelIteration": true,                       /* Emit more compliant, but verbose and less performant JavaScript for iteration. */
+    // "sourceRoot": "",                                 /* Specify the root path for debuggers to find the reference source code. */
+    // "mapRoot": "",                                    /* Specify the location where debugger should locate map files instead of generated locations. */
+    // "inlineSourceMap": true,                          /* Include sourcemap files inside the emitted JavaScript. */
+    // "inlineSources": true,                            /* Include source code in the sourcemaps inside the emitted JavaScript. */
+    // "emitBOM": true,                                  /* Emit a UTF-8 Byte Order Mark (BOM) in the beginning of output files. */
+    // "newLine": "crlf",                                /* Set the newline character for emitting files. */
+    // "stripInternal": true,                            /* Disable emitting declarations that have `@internal` in their JSDoc comments. */
+    // "noEmitHelpers": true,                            /* Disable generating custom helper functions like `__extends` in compiled output. */
+    // "noEmitOnError": true,                            /* Disable emitting files if any type checking errors are reported. */
+    // "preserveConstEnums": true,                       /* Disable erasing `const enum` declarations in generated code. */
+    // "declarationDir": "./",                           /* Specify the output directory for generated declaration files. */
+
+    /* Interop Constraints */
+    // "isolatedModules": true,                          /* Ensure that each file can be safely transpiled without relying on other imports. */
+    // "allowSyntheticDefaultImports": true,             /* Allow 'import x from y' when a module doesn't have a default export. */
+    "esModuleInterop": true,                             /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables `allowSyntheticDefaultImports` for type compatibility. */
+    // "preserveSymlinks": true,                         /* Disable resolving symlinks to their realpath. This correlates to the same flag in node. */
+    "forceConsistentCasingInFileNames": true,            /* Ensure that casing is correct in imports. */
+
+    /* Type Checking */
+    "strict": true,                                      /* Enable all strict type-checking options. */
+    // "noImplicitAny": true,                            /* Enable error reporting for expressions and declarations with an implied `any` type.. */
+    // "strictNullChecks": true,                         /* When type checking, take into account `null` and `undefined`. */
+    // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
+    // "strictBindCallApply": true,                      /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */
+    // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
+    // "noImplicitThis": true,                           /* Enable error reporting when `this` is given the type `any`. */
+    // "useUnknownInCatchVariables": true,               /* Type catch clause variables as 'unknown' instead of 'any'. */
+    // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
+    // "noUnusedLocals": true,                           /* Enable error reporting when a local variables aren't read. */
+    // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
+    // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
+    // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
+    // "noUncheckedIndexedAccess": true,                 /* Include 'undefined' in index signature results */
+    // "noImplicitOverride": true,                       /* Ensure overriding members in derived classes are marked with an override modifier. */
+    // "noPropertyAccessFromIndexSignature": true,       /* Enforces using indexed accessors for keys declared using an indexed type */
+    // "allowUnusedLabels": true,                        /* Disable error reporting for unused labels. */
+    // "allowUnreachableCode": true,                     /* Disable error reporting for unreachable code. */
+
+    /* Completeness */
+    // "skipDefaultLibCheck": true,                      /* Skip type checking .d.ts files that are included with TypeScript. */
+    "skipLibCheck": true,                                /* Skip type checking all .d.ts files. */
+    "noEmit": true,
+    "baseUrl": ".",
+    "paths": {
+      "@apis/*": ["src/apis/*"],
+      "@utils/*": ["src/utils/*"]
+    }
+  }
+}