feat(node-resolve): Add the ability to pass a function into resolveOn…

…ly (#1152)

* feat(node-resolve): Add the ability to pass a function into resolveOnly to resolve issue #1150

* Add a missing piece of text to the readme.

packages/node-resolve/README.md

@@ -140,12 +140,17 @@ If `true`, inspect resolved files to assert that they are ES2015 modules.
 
 ### `resolveOnly`
 
-Type: `Array[...String|RegExp]`<br>
+Type: `Array[...String|RegExp] | (module: string) => boolean`<br>
 Default: `null`
 
 An `Array` which instructs the plugin to limit module resolution to those whose names match patterns in the array. _Note: Modules not matching any patterns will be marked as external._
 
-Example: `resolveOnly: ['batman', /^@batcave\/.*$/]`
+Alternatively, you may pass in a function that returns a boolean to confirm whether the module should be included or not.
+
+Examples:
+
+- `resolveOnly: ['batman', /^@batcave\/.*$/]`
+- `resolveOnly: module => !module.includes('joker')`
 
 ### `rootDir`
 

packages/node-resolve/src/index.js

@@ -63,13 +63,22 @@ export function nodeResolve(opts = {}) {
       options.dedupe.includes(importee) || options.dedupe.includes(getPackageName(importee));
   }
 
-  const resolveOnly = options.resolveOnly.map((pattern) => {
-    if (pattern instanceof RegExp) {
-      return pattern;
-    }
-    const normalized = pattern.replace(/[\\^$*+?.()|[\]{}]/g, '\\$&');
-    return new RegExp(`^${normalized}$`);
-  });
+  // creates a function from the patterns to test if a particular module should be bundled.
+  const allowPatterns = (patterns) => {
+    const regexPatterns = patterns.map((pattern) => {
+      if (pattern instanceof RegExp) {
+        return pattern;
+      }
+      const normalized = pattern.replace(/[\\^$*+?.()|[\]{}]/g, '\\$&');
+      return new RegExp(`^${normalized}$`);
+    });
+    return (id) => !regexPatterns.length || regexPatterns.some((pattern) => pattern.test(id));
+  };
+
+  const resolveOnly =
+    typeof options.resolveOnly === 'function'
+      ? options.resolveOnly
+      : allowPatterns(options.resolveOnly);
 
   const browserMapCache = new Map();
   let preserveSymlinks;
@@ -112,11 +121,8 @@ export function nodeResolve(opts = {}) {
       isRelativeImport = true;
     }
 
-    if (
-      !isRelativeImport &&
-      resolveOnly.length &&
-      !resolveOnly.some((pattern) => pattern.test(id))
-    ) {
+    // if it's not a relative import, and it's not requested, reject it.
+    if (!isRelativeImport && !resolveOnly(id)) {
       if (normalizeInput(rollupOptions.input).includes(importee)) {
         return null;
       }

packages/node-resolve/test/only.js

@@ -68,3 +68,28 @@ test('regex', async (t) => {
   t.deepEqual(imports, ['test']);
   t.assert(Object.keys(modules).includes(resolve('only-local.js')));
 });
+
+test('allows a function as the parameter', async (t) => {
+  function allowed(...modules) {
+    const set = new Set(modules);
+    return (id) => set.has(id);
+  }
+
+  const warnings = [];
+  const bundle = await rollup({
+    input: ['only.js'],
+    onwarn: (warning) => warnings.push(warning),
+    plugins: [
+      nodeResolve({
+        resolveOnly: allowed('test')
+      })
+    ]
+  });
+  const imports = await getImports(bundle);
+  const modules = await getResolvedModules(bundle);
+
+  t.is(warnings.length, 0);
+  t.snapshot(warnings);
+  t.deepEqual(imports, ['@scoped/foo', '@scoped/bar']);
+  t.assert(Object.keys(modules).includes(resolve('only-local.js')));
+});

packages/node-resolve/test/snapshots/only.js.md

@@ -21,3 +21,9 @@ Generated by [AVA](https://avajs.dev).
 > Snapshot 1
 
     []
+
+## allows a function as the parameter
+
+> Snapshot 1
+
+    []

packages/node-resolve/types/index.d.ts

@@ -81,7 +81,7 @@ export interface RollupNodeResolveOptions {
    * names match patterns in the array.
    * @default []
    */
-  resolveOnly?: ReadonlyArray<string | RegExp> | null;
+  resolveOnly?: ReadonlyArray<string | RegExp> | null | ((module: string) => boolean);
 
   /**
    * Specifies the root directory from which to resolve modules. Typically used when