[feature] Add install script inputs

README.md

@@ -29,6 +29,26 @@ jobs:
       - uses: preactjs/compressed-size-action@v2
 ```
 
+### Customizing the Installation
+
+By default, `compressed-size-action` will install dependencies according to which lockfiles are present, if any. However, if you need to run a different installation command, you can pass a custom script to do so. For example, to use `npm ci` with the `--workspace` option:
+
+```diff
+name: Compressed Size
+
+on: [pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - uses: preactjs/compressed-size-action@v2
+      with:
++       install-script: "npm ci --workspace=packages/my-subpackage"
+```
+
 ### Customizing the Build
 
 By default, `compressed-size-action` will try to build your PR by running the `"build"` [npm script](https://docs.npmjs.com/misc/scripts) in your `package.json`.

action.yml

@@ -11,6 +11,9 @@ inputs:
     default: ${{ github.token }}
   clean-script:
     description: 'An npm-script that cleans/resets state between branch builds'
+  install-script:
+    required: false
+    description: 'The npm-script to run that install dependencies in your project'
   build-script:
     description: 'The npm-script to run that builds your project'
     default: 'build'

src/index.js

@@ -70,6 +70,10 @@ async function run(octokit, context, token) {
 		installScript = 'npm ci';
 	}
 
+	if (getInput('install-script')) {
+		installScript = getInput('install-script');
+	}
+
 	startGroup(`[current] Install Dependencies`);
 	console.log(`Installing using ${installScript}`);
 	await exec(installScript);
@@ -143,6 +147,10 @@ async function run(octokit, context, token) {
 		installScript = `npm ci`;
 	}
 
+	if (getInput('install-script')) {
+		installScript = getInput('install-script');
+	}
+
 	console.log(`Installing using ${installScript}`);
 	await exec(installScript);
 	endGroup();