feat: plugin factory function can be used to produce multiple instances

src/index.ts

@@ -86,7 +86,11 @@ export default function externalAssets(pattern: FilterPattern, options?: PluginO
 				],
 			}
 		},
-		async resolveId(source, importer) {
+		async resolveId(source, importer, options) {
+			// `this.resolve` was called from another instance of this plugin.
+			// skip to avoid infinite loop.
+			if (options.custom?.[PLUGIN_NAME]?.skip) return null;
+
 			// Skip resolving entrypoints,
 			// and don't resolve imports from filtered out modules.
 			if (!importer || !importerFilter(importer)) return null;
@@ -96,6 +100,11 @@ export default function externalAssets(pattern: FilterPattern, options?: PluginO
 			// We need to skip this plugin to avoid an infinite loop.
 			const resolution = await this.resolve(source, importer, {
 				skipSelf: true,
+				custom: {
+					[PLUGIN_NAME]: {
+						skip: true,
+					}
+				}
 			});
 
 			// If it cannot be resolved, or if the id is filtered out,

tests/general.test.js

@@ -1,6 +1,7 @@
 const test = require("ava");
 const { nodeResolve } = require("@rollup/plugin-node-resolve");
 const { rollup } = require("rollup");
+const { outputSnapshotMacro } = require("./macros");
 const externalAssets = require("..");
 
 const falsy = [undefined, null, false, "", NaN, 0];
@@ -29,3 +30,16 @@ test("Plugin works even if it's not the first in the list", async t => {
 		})
 	);
 });
+
+test("Multiple instances of the plugin can be used at the same time", outputSnapshotMacro,
+	{
+		input: "tests/fixtures/src/index2.js",
+		plugins: [
+			externalAssets("tests/fixtures/assets/*"),
+			nodeResolve({
+				moduleDirectories: ["tests/fixtures/node_modules"],
+			}),
+			externalAssets(/@fontsource\/open-sans/),
+		],
+	}
+);

tests/resolve.test.js

@@ -6,7 +6,7 @@ const externalAssets = require("..");
 
 test("Skips resolving entrypoints", async t => {
 	const plugin = externalAssets("dummy_patern");
-	const resolution = await plugin.resolveId("dummy_source", undefined);
+	const resolution = await plugin.resolveId("dummy_source", undefined, {});
 
 	t.is(resolution, null);
 });