diff --git a/theatre/devEnv/buildUtils.ts b/theatre/devEnv/buildUtils.ts
index 48d1038..43665a7 100644
--- a/theatre/devEnv/buildUtils.ts
+++ b/theatre/devEnv/buildUtils.ts
@@ -1,6 +1,59 @@
+import path from 'path'
+import {build} from 'esbuild'
+
 export const definedGlobals = {
   global: 'window',
   'process.env.version': JSON.stringify(
     require('../studio/package.json').version,
   ),
 }
+
+export function createBundles(watch: boolean) {
+  for (const which of ['core', 'studio']) {
+    const pathToPackage = path.join(__dirname, '../', which)
+    const esbuildConfig: Parameters<typeof build>[0] = {
+      entryPoints: [path.join(pathToPackage, 'src/index.ts')],
+      target: ['es6'],
+      loader: {'.png': 'file'},
+      bundle: true,
+      sourcemap: true,
+      define: definedGlobals,
+      watch,
+      external: ['@theatre/dataverse'],
+    }
+
+    if (which === 'core') {
+      esbuildConfig.platform = 'neutral'
+      esbuildConfig.mainFields = ['browser', 'module', 'main']
+      esbuildConfig.target = ['firefox57', 'chrome58']
+      esbuildConfig.conditions = ['browser', 'node']
+    }
+
+    build({
+      ...esbuildConfig,
+      outfile: path.join(pathToPackage, 'dist/index.cjs'),
+      format: 'cjs',
+    })
+
+    build({
+      ...esbuildConfig,
+      outfile: path.join(pathToPackage, 'dist/index.mjs'),
+      format: 'esm',
+    })
+
+    build({
+      ...esbuildConfig,
+      outfile: path.join(pathToPackage, 'dist/index.min.js'),
+      format: 'iife',
+      external: [],
+      minify: true,
+      globalName: `Theatre.${which}`,
+      legalComments: 'external',
+      platform: 'browser',
+      define: {
+        ...definedGlobals,
+        'process.env.NODE_ENV': JSON.stringify('production'),
+      },
+    })
+  }
+}
diff --git a/theatre/devEnv/bundle.ts b/theatre/devEnv/bundle.ts
index 532f916..8821401 100644
--- a/theatre/devEnv/bundle.ts
+++ b/theatre/devEnv/bundle.ts
@@ -1,54 +1,3 @@
-import path from 'path'
-import {definedGlobals} from './buildUtils'
-import {build} from 'esbuild'
+import {createBundles} from './buildUtils'
 
-createBundles()
-
-function createBundles() {
-  for (const which of ['core', 'studio']) {
-    const pathToPackage = path.join(__dirname, '../', which)
-    const esbuildConfig: Parameters<typeof build>[0] = {
-      entryPoints: [path.join(pathToPackage, 'src/index.ts')],
-      target: ['firefox88', 'chrome90'],
-      loader: {'.png': 'file'},
-      bundle: true,
-      sourcemap: true,
-      define: definedGlobals,
-      external: ['@theatre/dataverse'],
-    }
-
-    if (which === 'core') {
-      esbuildConfig.platform = 'neutral'
-      esbuildConfig.mainFields = ['browser', 'module', 'main']
-      esbuildConfig.target = ['firefox57', 'chrome58']
-      esbuildConfig.conditions = ['browser', 'node']
-    }
-
-    build({
-      ...esbuildConfig,
-      outfile: path.join(pathToPackage, 'dist/index.cjs'),
-      format: 'cjs',
-    })
-
-    build({
-      ...esbuildConfig,
-      outfile: path.join(pathToPackage, 'dist/index.mjs'),
-      format: 'esm',
-    })
-
-    build({
-      ...esbuildConfig,
-      outfile: path.join(pathToPackage, 'dist/index.min.js'),
-      format: 'iife',
-      external: [],
-      minify: true,
-      globalName: `Theatre.${which}`,
-      legalComments: 'external',
-      platform: 'browser',
-      define: {
-        ...definedGlobals,
-        'process.env.NODE_ENV': JSON.stringify('production'),
-      },
-    })
-  }
-}
+createBundles(false)
diff --git a/theatre/devEnv/watch.ts b/theatre/devEnv/watch.ts
new file mode 100644
index 0000000..f8f5d1d
--- /dev/null
+++ b/theatre/devEnv/watch.ts
@@ -0,0 +1,3 @@
+import {createBundles} from './buildUtils'
+
+createBundles(true)
diff --git a/theatre/package.json b/theatre/package.json
index a0a4c96..43452aa 100644
--- a/theatre/package.json
+++ b/theatre/package.json
@@ -7,6 +7,7 @@
   "scripts": {
     "typecheck": "tsc --build",
     "build:js": "node -r esbuild-register devEnv/bundle.ts",
+    "build:js:watch": "node -r esbuild-register devEnv/watch.ts",
     "build:dts": "run-s typecheck build:dts:bundle",
     "build:dts:bundle": "rollup -c devEnv/declarations-bundler/rollup.config.js",
     "build": "run-p build:dts build:js",