Implement absoluteImports option

docs/usage.md

@@ -74,6 +74,16 @@ The `shouldInjectPolyfill` function takes two parameters: the name of the polyfi
 function shouldInjectPolyfill(name: string, defaultShouldInject: boolean): boolean;
 ```
 
+### `absoluteRuntime`
+
+`boolean` or `string`, defaults to `false`.
+
+This allows users to run polyfill providers broadly across a whole project. By default, polyfill providers inject a bare import to the polyfill package (for example, `core-js-pure/stable/array/from.js`), but that only works if the polyfill is in the `node_modules` of the file that is being compiled. This can be problematic for nested `node_modules`, npm-linked modules, or CLIs that reside outside the user's project, among other cases. To avoid worrying about how the runtime module's location is resolved, this allows users to resolve the runtime once up front, and then insert absolute paths to the runtime into the output code.
+
+Using absolute paths is not desirable if files are compiled for use at a later time, but in contexts where a file is compiled and then immediately consumed, they can be quite helpful.
+
+Reference: [babel/babel#8435](https://github.com/babel/babel/pull/8435)
+
 ### `missingDependencies`
 
 This option modifies the dependencies detection logging. If set to `false`, dependencies

packages/babel-helper-define-polyfill-provider/src/dependencies.js

@@ -1,11 +1,59 @@
 // @flow
 
-import resolve from "resolve";
+import requireResolve from "resolve";
+import path from "path";
 import debounce from "lodash.debounce";
 
+export function resolve(
+  dirname: string,
+  moduleName: string,
+  absoluteImports: boolean | string,
+): string {
+  if (absoluteImports === false) return moduleName;
+
+  let basedir = dirname;
+  if (typeof absoluteImports === "string") {
+    basedir = path.resolve(basedir, absoluteImports);
+  }
+
+  let modulePackage, moduleNestedPath;
+
+  let slash = moduleName.indexOf("/");
+  if (moduleName[0] === "@") {
+    slash = moduleName.indexOf("/", slash + 1);
+  }
+
+  if (slash === -1) {
+    modulePackage = moduleName;
+    moduleNestedPath = "";
+  } else {
+    modulePackage = moduleName.slice(0, slash);
+    moduleNestedPath = moduleName.slice(slash);
+  }
+
+  try {
+    const pkg = requireResolve.sync(`${modulePackage}/package.json`, {
+      basedir,
+    });
+    return path.dirname(pkg) + moduleNestedPath;
+  } catch (err) {
+    if (err.code !== "MODULE_NOT_FOUND") throw err;
+
+    // $FlowIgnore
+    throw Object.assign(
+      new Error(`Failed to resolve "${moduleName}" relative to "${dirname}"`),
+      {
+        code: "BABEL_POLYFILL_NOT_FOUND",
+        polyfill: moduleName,
+        dirname,
+      },
+    );
+  }
+}
+
 export function has(basedir: string, name: string) {
   try {
-    resolve.sync(name, { basedir });
+    requireResolve.sync(name, { basedir });
     return true;
   } catch {
     return false;

packages/babel-helper-define-polyfill-provider/src/imports-cache.js

@@ -9,11 +9,13 @@ export default class ImportsCache {
   _imports: WeakMap<NodePath, StrMap<string>>;
   _anonymousImports: WeakMap<NodePath, Set<string>>;
   _lastImports: WeakMap<NodePath, NodePath>;
+  _resolver: (url: string) => string;
 
-  constructor() {
+  constructor(resolver: (url: string) => string) {
     this._imports = new WeakMap();
     this._anonymousImports = new WeakMap();
     this._lastImports = new WeakMap();
+    this._resolver = resolver;
   }
 
   storeAnonymous(
@@ -29,7 +31,7 @@ export default class ImportsCache {
 
     const node = getVal(
       programPath.node.sourceType === "script",
-      t.stringLiteral(url),
+      t.stringLiteral(this._resolver(url)),
     );
     imports.add(key);
     this._injectImport(programPath, node);
@@ -53,7 +55,7 @@ export default class ImportsCache {
     if (!imports.has(key)) {
       const { node, name: id } = getVal(
         programPath.node.sourceType === "script",
-        t.stringLiteral(url),
+        t.stringLiteral(this._resolver(url)),
         t.identifier(name),
       );
       imports.set(key, id);

packages/babel-helper-define-polyfill-provider/src/index.js

@@ -45,6 +45,7 @@ function resolveOptions<Options>(
   debug: boolean,
   shouldInjectPolyfill: ?(name: string, shouldInject: boolean) => boolean,
   providerOptions: ProviderOptions<Options>,
+  absoluteImports: string | boolean,
 } {
   const {
     method,
@@ -53,6 +54,7 @@ function resolveOptions<Options>(
     configPath,
     debug,
     shouldInjectPolyfill,
+    absoluteImports,
     ...providerOptions
   } = options;
 
@@ -83,6 +85,17 @@ function resolveOptions<Options>(
     );
   }
 
+  if (
+    absoluteImports != null &&
+    typeof absoluteImports !== "boolean" &&
+    typeof absoluteImports !== "string"
+  ) {
+    throw new Error(
+      `.absoluteImports must be a boolean, a string, or undefined` +
+        ` (received ${JSON.stringify(absoluteImports)})`,
+    );
+  }
+
   const targetsObj =
     typeof targetsOption === "string" || Array.isArray(targetsOption)
       ? { browsers: targetsOption }
@@ -97,6 +110,7 @@ function resolveOptions<Options>(
     method,
     methodName,
     targets,
+    absoluteImports: absoluteImports ?? false,
     shouldInjectPolyfill,
     debug: !!debug,
     providerOptions: ((providerOptions: Object): ProviderOptions<Options>),
@@ -118,9 +132,14 @@ function instantiateProvider<Options>(
     debug,
     shouldInjectPolyfill,
     providerOptions,
+    absoluteImports,
   } = resolveOptions<Options>(options);
 
-  const getUtils = createUtilsGetter(new ImportsCache());
+  const getUtils = createUtilsGetter(
+    new ImportsCache(moduleName =>
+      deps.resolve(dirname, moduleName, absoluteImports),
+    ),
+  );
 
   // eslint-disable-next-line prefer-const
   let include, exclude;
@@ -180,12 +199,18 @@ function instantiateProvider<Options>(
     },
     assertDependency(name, version = "*") {
       if (missingDependencies === false) return;
+      if (absoluteImports) {
+        // If absoluteImports is not false, we will try resolving
+        // the dependency and throw if it's not possible. We can
+        // skip the check here.
+        return;
+      }
 
       const dep = version === "*" ? name : `${name}@^${version}`;
 
       const found = missingDependencies.all
         ? false
-        : mapGetOr(depsCache, name, () => deps.has(dirname, name));
+        : mapGetOr(depsCache, name, () => !deps.has(dirname, name));
 
       if (!found) {
         debugLog().missingDeps.add(dep);

packages/babel-helper-define-polyfill-provider/src/types.js

@@ -33,6 +33,7 @@ export type PluginOptions = {|
   exclude?: Pattern[],
   shouldInjectPolyfill?: (name: string, shouldInject: boolean) => boolean,
   missingDependencies?: MissingDependenciesOption,
+  absoluteImports?: boolean | string,
 |};
 
 export type PolyfillProvider<Opts = {||}> = (

packages/babel-helper-define-polyfill-provider/test/absolute-imports.js

@@ -0,0 +1,52 @@
+import * as babel from "@babel/core";
+import { join } from "path";
+import { readFileSync, writeFileSync } from "fs";
+
+function transformTest(name, cwd, file, options = {}) {
+  it(name, () => {
+    const inputPath = join(cwd, file);
+    const outputPath = join(cwd, file.replace(".js", ".out.js"));
+
+    const input = readFileSync(inputPath, "utf8");
+    let expected;
+    try {
+      expected = readFileSync(outputPath, "utf8");
+    } catch {}
+
+    let { code } = babel.transformSync(input, {
+      cwd,
+      filename: inputPath,
+      ...options,
+    });
+
+    while (code.includes(__dirname)) {
+      code = code.replace(__dirname, "<CWD>");
+    }
+
+    if (expected === undefined) {
+      writeFileSync(outputPath, code);
+    } else {
+      expect(code).toBe(expected);
+    }
+  });
+}
+
+describe("true", () => {
+  const cwd = join(__dirname, "fixtures", "absoluteImports", "true");
+
+  transformTest("basic behavior", cwd, "main.js");
+  transformTest("relative to config file", cwd, "nested/main.js");
+  transformTest("resolved in a parent directory", cwd, "nested-2/main.js");
+});
+
+describe("string", () => {
+  const cwd = join(__dirname, "fixtures", "absoluteImports", "string");
+
+  transformTest("basic behavior", cwd, "main.js");
+});
+
+describe("subpath", () => {
+  const cwd = join(__dirname, "fixtures", "absoluteImports", "subpath");
+
+  transformTest("works", cwd, "main.js");
+});

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/string/babel.config.json

@@ -0,0 +1,12 @@
+{
+  "plugins": [
+    ["../../../helpers/generic-provider.js", {
+      "method": "usage-global",
+      "globals": {
+        "a": "polyfill-a",
+        "b": "polyfill-b"
+      },
+      "absoluteImports": "./nested"
+    }, "polyfill-a"]
+  ]
+}

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/string/main.js

@@ -0,0 +1,2 @@
+a;
+b;

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/string/main.out.js

@@ -0,0 +1,4 @@
+import "<CWD>/fixtures/absoluteImports/string/nested/node_modules/polyfill-a";
+import "<CWD>/fixtures/absoluteImports/string/node_modules/polyfill-b";
+a;
+b;

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/subpath/babel.config.json

@@ -0,0 +1,12 @@
+{
+  "plugins": [
+    ["../../../helpers/generic-provider.js", {
+      "method": "usage-global",
+      "globals": {
+        "a": "polyfill-a/auto",
+        "b": "@polyfill/b/auto"
+      },
+      "absoluteImports": true
+    }]
+  ]
+}

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/subpath/main.js

@@ -0,0 +1,2 @@
+a;
+b;

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/subpath/main.out.js

@@ -0,0 +1,4 @@
+import "<CWD>/fixtures/absoluteImports/subpath/node_modules/polyfill-a/auto";
+import "<CWD>/fixtures/absoluteImports/subpath/node_modules/@polyfill/b/auto";
+a;
+b;

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/true/babel.config.json

@@ -0,0 +1,12 @@
+{
+  "babelrcRoots": ["./nested", "./nested-2"],
+  "plugins": [
+    ["../../../helpers/generic-provider.js", {
+      "method": "usage-global",
+      "globals": {
+        "a": "polyfill-a"
+      },
+      "absoluteImports": true
+    }, "polyfill-a"]
+  ]
+}

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/true/main.js

@@ -0,0 +1 @@
+a;

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/true/main.out.js

@@ -0,0 +1,2 @@
+import "<CWD>/fixtures/absoluteImports/true/node_modules/polyfill-a";
+a;

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/true/nested-2/.babelrc.json

@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    ["../../../../helpers/generic-provider.js", {
+      "method": "usage-global",
+      "globals": {
+        "b": "polyfill-b"
+      },
+      "absoluteImports": true
+    }, "polyfill-b"]
+  ]
+}

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/true/nested-2/main.js

@@ -0,0 +1,2 @@
+a;
+b;

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/true/nested-2/main.out.js

@@ -0,0 +1,4 @@
+import "<CWD>/fixtures/absoluteImports/true/node_modules/polyfill-b";
+import "<CWD>/fixtures/absoluteImports/true/node_modules/polyfill-a";
+a;
+b;

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/true/nested/.babelrc.json

@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    ["../../../../helpers/generic-provider.js", {
+      "method": "usage-global",
+      "globals": {
+        "b": "polyfill-b"
+      },
+      "absoluteImports": true
+    }, "polyfill-b"]
+  ]
+}

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/true/nested/main.js

@@ -0,0 +1,2 @@
+a;
+b;

packages/babel-helper-define-polyfill-provider/test/fixtures/absoluteImports/true/nested/main.out.js

@@ -0,0 +1,4 @@
+import "<CWD>/fixtures/absoluteImports/true/nested/node_modules/polyfill-b";
+import "<CWD>/fixtures/absoluteImports/true/node_modules/polyfill-a";
+a;
+b;