fix: do not crash on empty async hook (#42)

Author: evilebottnawi

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+<!--lint disable -->
+<!-- prettier-ignore-start -->
+
 All notable changes to this project will be documented in this file. See [standard-version](https://github.com/conventional-changelog/standard-version) for commit guidelines.
 
 ### [6.0.1](https://github.com/itgalaxy/execa-webpack-plugin/compare/v6.0.0...v6.0.1) (2020-02-26)
@@ -97,3 +100,5 @@ All notable changes to this project will be documented in this file. See [standa
 ## 1.0.0 - 2017-12-22
 
 - Chore: public initial release.
+
+<!-- prettier-ignore-end -->

__tests__/__snapshots__/index.test.js.snap

@@ -134,7 +134,33 @@ Array [
 
 exports[`execa-webpack-plugin should not throw error with 'bail: false' option (sync hook): warnings 1`] = `Array []`;
 
-exports[`execa-webpack-plugin should output warning on empty hook: logs 1`] = `
+exports[`execa-webpack-plugin should output warning on empty async hook: logs 1`] = `
+Array [
+  Array [
+    "ExecaPlugin",
+    "log",
+    Array [
+      "Running the \\"done\\" hook",
+    ],
+  ],
+  Array [
+    "ExecaPlugin",
+    "warn",
+    Array [
+      "No commands found for the \\"done\\" hook",
+    ],
+  ],
+  Array [
+    "ExecaPlugin",
+    "log",
+    Array [
+      "The \\"done\\" hook completed",
+    ],
+  ],
+]
+`;
+
+exports[`execa-webpack-plugin should output warning on empty sync hook: logs 1`] = `
 Array [
   Array [
     "ExecaPlugin",

__tests__/helpers/normalize-errors.js

@@ -10,9 +10,8 @@ function removeCWD(str) {
   }
 
   if (isWin) {
-    // eslint-disable-next-line no-param-reassign, unicorn/prefer-replace-all
+    // eslint-disable-next-line no-param-reassign
     str = str.replace(/\\/g, "/");
-    // eslint-disable-next-line unicorn/prefer-replace-all
     cwd = cwd.replace(/\\/g, "/");
   }
 

__tests__/index.test.js

@@ -146,14 +146,22 @@ describe("execa-webpack-plugin", () => {
     expect(logs).toMatchSnapshot("logs");
   });
 
-  it("should output warning on empty hook", async () => {
+  it("should output warning on empty sync hook", async () => {
     await compile({
       onCompile: []
     });
 
     expect(logs).toMatchSnapshot("logs");
   });
 
+  it("should output warning on empty async hook", async () => {
+    await compile({
+      onDone: []
+    });
+
+    expect(logs).toMatchSnapshot("logs");
+  });
+
   it("should work with 'on*' options", async () => {
     const stats = await compile({
       onShouldEmit: [

src/ExecaWebpackPlugin.js

@@ -135,7 +135,7 @@ class ExecaPlugin {
         )}" hook`
       );
 
-      return [];
+      return Promise.resolve();
     }
 
     const results = commands