diff --git a/bin/install-addons.js b/bin/install-addons.js
new file mode 100644
index 0000000000..83adea1f05
--- /dev/null
+++ b/bin/install-addons.js
@@ -0,0 +1,56 @@
+/**
+ * Copyright (c) 2019 The xterm.js authors. All rights reserved.
+ * @license MIT
+ *
+ * Script to initialize addon packages under "addons/" with outer deps.
+ */
+
+const path = require('path');
+const cp = require('child_process');
+const fs = require('fs');
+
+const PACKAGE_ROOT = path.join(__dirname, '..');
+
+// install addon deps
+const addonsPath = path.join(PACKAGE_ROOT, 'addons');
+if (fs.existsSync(addonsPath)) {
+  console.log('pulling addon dependencies...');
+
+  // whether to use yarn or npm
+  let hasYarn = false;
+  try {
+    cp.execSync('yarn --version').toString();
+    hasYarn = true;
+  } catch(e) {}
+
+  // walk all addon folders
+  fs.readdir(addonsPath, (err, files) => {
+    files.forEach(folder => {
+      const addonPath = path.join(addonsPath, folder);
+
+      // install only if there are dependencies listed
+      let packageJson;
+      try {
+        packageJson = require(path.join(addonPath, 'package.json'));
+      } catch (e) {
+        // swallow as changing branches can leave folders around
+      }
+      if (packageJson
+            && (
+              (packageJson.devDependencies && Object.keys(packageJson.devDependencies).length)
+              || (packageJson.dependencies && Object.keys(packageJson.dependencies).length)
+            )
+          )
+      {
+        console.log('Preparing', folder);
+        if (hasYarn) {
+          cp.execSync('yarn', {cwd: addonPath});
+        } else {
+          cp.execSync('npm install', {cwd: addonPath});
+        }
+      } else {
+        console.log('Skipped', folder);
+      }
+    });
+  });
+}
diff --git a/package.json b/package.json
index 8174bbf5a5..fb9592c757 100644
--- a/package.json
+++ b/package.json
@@ -11,13 +11,15 @@
     "prepackage": "npm run build",
     "package": "webpack",
     "start": "node demo/start",
-    "lint": "tslint 'src/**/*.ts' 'addons/**/*.ts'",
+    "lint": "tslint 'src/**/*.ts' 'addons/*/src/**/*.ts'",
     "test": "npm run test-unit",
     "posttest": "npm run lint",
     "test-api": "mocha \"**/*.api.js\"",
     "test-unit": "node ./bin/test.js",
     "build": "tsc -b ./tsconfig.all.json",
-    "prepare": "npm run build",
+    "prepare": "npm run setup",
+    "setup": "npm run build",
+    "presetup": "node ./bin/install-addons.js",
     "prepublishOnly": "npm run package",
     "watch": "tsc -b -w ./tsconfig.all.json --preserveWatchOutput",
     "benchmark": "NODE_PATH=./out xterm-benchmark -r 5 -c test/benchmark/benchmark.json",