split up import/export rewrites and add some tests for logic

fix a bug too in the process

.gitignore

@@ -1 +1,2 @@
-node_modules
+node_modules
+coverage

.vscode/launch.json

@@ -23,6 +23,15 @@
       "args": ["--port=3000", "--docRoot=static", "--scriptRoot=js"],
       "console": "integratedTerminal",
       "internalConsoleOptions": "neverOpen"
+    },
+    {
+      "type": "node",
+      "request": "launch",
+      "name": "Tests",
+      "program": "${workspaceFolder}/node_modules/.bin/tead",
+      "args": ["--watch"],
+      "console": "integratedTerminal",
+      "internalConsoleOptions": "neverOpen"
     }
   ]
 }

package.json

@@ -10,14 +10,18 @@
     "srvs": "./src/index.js"
   },
   "devDependencies": {
-    "eslint": "=5.4.0"
+    "eslint": "=5.4.0",
+    "tead": "=0.5.0"
   },
   "scripts": {
-    "format": "npx prettier --write '{src,examples,!(node_modules)/}/**/*.js'",
-    "format:check": "prettier --list-different '{src,examples,!(node_modules)/}/**/*.js'",
+    "clean": "npx rimraf coverage node_modules",
+    "format": "npx prettier --write '{src,examples,!(node_modules|coverage)/}/**/*.js'",
+    "format:check": "prettier --list-different '{src,examples,!(node_modules|coverage)/}/**/*.js'",
     "lint": "eslint src/**/*.js",
-    "check": "npm run format:check && npm run lint",
-    "release": "./pre-flight-tests && npm run check && git tag $npm_package_version && git push && git push --tags && npm publish"
+    "test": "tead --coverage",
+    "check": "npm run format:check && npm run lint && npm t",
+    "prepare": "npm run check",
+    "release": "./pre-flight-tests && npm run clean && npm i && git tag $npm_package_version && git push && git push --tags && npm publish"
   },
   "eslintConfig": {
     "extends": "eslint:recommended",

src/server/getImportInfo.js

@@ -0,0 +1,43 @@
+const fs = require("fs");
+const path = require("path");
+
+module.exports = ({ importPath, searchPath }) => {
+  const nodeModulesPath = path.resolve(searchPath, "node_modules");
+  const moduleName = importPath
+    .split("/")
+    .slice(0, importPath.startsWith("@") ? 2 : 1)
+    .join("/");
+  const projectPackagePath = path.resolve(searchPath, "package.json");
+  delete require.cache[projectPackagePath];
+  const projectPackage = require(projectPackagePath);
+  const moduleVersion = (projectPackage.dependencies || {})[moduleName];
+  const installedModulePath = path.resolve(nodeModulesPath, moduleName);
+  const isInstalled = fs.existsSync(installedModulePath);
+  let resolvedImportPath;
+
+  if (moduleName === importPath) {
+    try {
+      const modulePackagePath = path.resolve(
+        installedModulePath,
+        "package.json"
+      );
+      delete require.cache[modulePackagePath];
+      const { module } = require(modulePackagePath);
+      resolvedImportPath = path.resolve(installedModulePath, module);
+    } catch (e) {
+      // not installed
+    }
+  } else {
+    resolvedImportPath = require.resolve(importPath, {
+      paths: [nodeModulesPath]
+    });
+  }
+
+  return {
+    moduleName,
+    moduleVersion,
+    installedModulePath,
+    resolvedImportPath,
+    isInstalled
+  };
+};

src/server/rewriteImportsAndExports.js

@@ -0,0 +1,33 @@
+const path = require("path");
+const getImportInfo = require("./getImportInfo");
+const normalizePath = require("../normalizePath");
+
+const ES6_IMPORT_REGEX = /(import[\s\S]+?from)\s+?['"]([^"']+)["']?;?/g;
+const ES6_EXPORT_REGEX = /(export[\s\S]+?from)\s+?['"]([^"']+)["']?;?/g;
+
+module.exports = ({ contents = "", searchPath = "", importContext = "" }) =>
+  contents
+    .replace(ES6_IMPORT_REGEX, (match, imports, module) => {
+      if (module.startsWith(".")) {
+        return match;
+      }
+      const { isInstalled, moduleName, moduleVersion } = getImportInfo({
+        importPath: module,
+        searchPath
+      });
+      if (isInstalled) {
+        return `${imports} "/node_modules/${module}"`;
+      }
+      return `${imports} "https://unpkg.com/${moduleName}${
+        moduleVersion ? `@${moduleVersion}` : ""
+      }?module"`;
+    })
+    .replace(ES6_EXPORT_REGEX, (_, exports, module) => {
+      const resolvedRelativeImport =
+        (importContext && path.dirname(module) !== ".") ||
+        !path.basename(module).includes(".")
+          ? normalizePath(path.join(importContext, module))
+          : module;
+      const importPrefix = resolvedRelativeImport.startsWith(".") ? "" : ".";
+      return `${exports} "${importPrefix}${resolvedRelativeImport}"`;
+    });

src/server/streamPath.js

@@ -1,52 +1,12 @@
 const fs = require("fs");
 const path = require("path");
 const stream = require("stream");
+const getImportInfo = require("./getImportInfo");
+const rewriteImportsAndExports = require("./rewriteImportsAndExports");
 const normalizePath = require("../normalizePath");
 const mimeLookup = require("./mimeLookup");
-
-const ES6_IMPORT_REGEX = /(import[\s\S]+?from)\s+?['"]([^"']+)["']?;?/g;
-const ES6_EXPORT_REGEX = /(export[\s\S]+?from)\s+?['"]([^"']+)["']?;?/g;
 const NODE_MODULES_REGEX = /^\/node_modules\//;
 
-const getImportInfo = ({ importPath, searchPath }) => {
-  const nodeModulesPath = path.resolve(searchPath, "node_modules");
-  const moduleName = importPath
-    .split("/")
-    .slice(0, importPath.startsWith("@") ? 2 : 1)
-    .join("/");
-  const projectPackagePath = path.resolve(searchPath, "package.json");
-  delete require.cache[projectPackagePath];
-  const projectPackage = require(projectPackagePath);
-  const moduleVersion = (projectPackage.dependencies || {})[moduleName];
-  const installedModulePath = path.resolve(nodeModulesPath, moduleName);
-  let resolvedImportPath;
-
-  if (moduleName === importPath) {
-    try {
-      const modulePackagePath = path.resolve(
-        installedModulePath,
-        "package.json"
-      );
-      delete require.cache[modulePackagePath];
-      const { module } = require(modulePackagePath);
-      resolvedImportPath = path.resolve(installedModulePath, module);
-    } catch (e) {
-      // not installed
-    }
-  } else {
-    resolvedImportPath = require.resolve(importPath, {
-      paths: [nodeModulesPath]
-    });
-  }
-
-  return {
-    moduleName,
-    moduleVersion,
-    installedModulePath,
-    resolvedImportPath
-  };
-};
-
 const rewrite = (rewritter = chunk => chunk) =>
   new stream.Transform({
     transform(chunk, _, next) {
@@ -57,33 +17,8 @@ const rewrite = (rewritter = chunk => chunk) =>
   });
 
 const rewriteScript = ({ searchPath, importContext }) =>
-  rewrite(chunk =>
-    chunk
-      .replace(ES6_IMPORT_REGEX, (match, imports, module) => {
-        if (module.startsWith(".")) {
-          return match;
-        }
-        const {
-          moduleName,
-          moduleVersion,
-          installedModulePath
-        } = getImportInfo({
-          importPath: module,
-          searchPath
-        });
-        if (fs.existsSync(installedModulePath)) {
-          return `${imports} "/node_modules/${module}"`;
-        }
-        return `${imports} "https://unpkg.com/${moduleName}${
-          moduleVersion ? `@${moduleVersion}` : ""
-        }?module"`;
-      })
-      .replace(ES6_EXPORT_REGEX, (_, exports, module) => {
-        const resolvedRelativeImport = importContext
-          ? normalizePath(path.join(importContext, module))
-          : module;
-        return `${exports} ".${resolvedRelativeImport}"`;
-      })
+  rewrite(contents =>
+    rewriteImportsAndExports({ contents, searchPath, importContext })
   );
 
 const streamFile = ({

test/server/fake-project/installed/.gitignore

@@ -0,0 +1 @@
+!node_modules

test/server/fake-project/installed/package.json

@@ -0,0 +1,8 @@
+{
+  "name": "fake-project",
+  "version": "0.0.0",
+  "private": true,
+  "dependencies": {
+    "fake-package": "1.0.0"
+  }
+}

test/server/fake-project/not-installed/no-version/package.json

@@ -0,0 +1,5 @@
+{
+  "name": "fake-project",
+  "version": "0.0.0",
+  "private": true
+}

test/server/fake-project/not-installed/with-version/package.json

@@ -0,0 +1,8 @@
+{
+  "name": "fake-project",
+  "version": "0.0.0",
+  "private": true,
+  "dependencies": {
+    "fake-package": "1.0.0"
+  }
+}

test/server/rewriteImportsAndExports.test.js

@@ -0,0 +1,90 @@
+const path = require("path");
+
+const fakeProjectPath = path.join(__dirname, "fake-project");
+
+const rewriteImportsAndExports = require("../../src/server/rewriteImportsAndExports");
+export default {
+  rewriteImportsAndExports: {
+    "should be a function": [typeof rewriteImportsAndExports, "function"],
+    imports: {
+      "should not modify relative imports": [
+        rewriteImportsAndExports({
+          contents: `import something from "./somewhere"`
+        }),
+        `import something from "./somewhere"`
+      ],
+      absolute: {
+        "not installed": {
+          "without version should rewrite to default unpkg": [
+            rewriteImportsAndExports({
+              contents: `import { app, h } from "fake-package"`,
+              searchPath: path.join(
+                fakeProjectPath,
+                "not-installed",
+                "no-version"
+              )
+            }),
+            `import { app, h } from "https://unpkg.com/fake-package?module"`
+          ],
+          "with version should rewrite to unpkg with version": [
+            rewriteImportsAndExports({
+              contents: `import { app, h } from "fake-package"`,
+              searchPath: path.join(
+                fakeProjectPath,
+                "not-installed",
+                "with-version"
+              )
+            }),
+            `import { app, h } from "https://unpkg.com/fake-package@1.0.0?module"`
+          ]
+        },
+        installed: {
+          "with version should rewrite to local node_modules": [
+            rewriteImportsAndExports({
+              contents: `import { app, h } from "fake-package"`,
+              searchPath: path.join(fakeProjectPath, "installed")
+            }),
+            `import { app, h } from "/node_modules/fake-package"`
+          ]
+        }
+      }
+    },
+    exports: {
+      "should resolve relative subfolder to index without extension": [
+        rewriteImportsAndExports({
+          contents: `export { default } from "./subfolder/index"`,
+          importContext: "/folder"
+        }),
+        `export { default } from "./folder/subfolder/index"`
+      ],
+      "should resolve relative subfolder to index with extension": [
+        rewriteImportsAndExports({
+          contents: `export { default } from "./subfolder/index.js"`,
+          importContext: "/folder"
+        }),
+        `export { default } from "./folder/subfolder/index.js"`
+      ],
+      "should resolve relative subfolder to non index file with extension": [
+        rewriteImportsAndExports({
+          contents: `export { default } from "./somewhere/name.js"`,
+          importContext: "/test"
+        }),
+        `export { default } from "./test/somewhere/name.js"`
+      ],
+      "should resolve relative root to non index file without extension": [
+        rewriteImportsAndExports({
+          contents: `export { default } from "./name"`,
+          importContext: "/folder"
+        }),
+        `export { default } from "./folder/name"`
+      ],
+      "should resolve relative root to non index file with extension": [
+        rewriteImportsAndExports({
+          contents: `export { default } from "./name.js"`,
+          importContext: "/folder"
+        }),
+        `export { default } from "./name.js"`
+      ]
+    }
+  }
+};