Dynamic imports

CHANGELOG.md

@@ -1,3 +1,7 @@
+## master
+
+- dynamic ESM imports through `nodo.import`
+
 ## 1.6.3
 
 - use Nodo.timeout for all JS calls

README.md

@@ -91,6 +91,23 @@ class FooBar < Nodo::Core
 end
 ```
 
+### Dynamic ESM imports
+
+ES modules can be imported dynamically using `nodo.import()`:
+
+```ruby
+class DynamicFoo < Nodo::Core
+  function :v4, <<~JS
+    async () => {
+      const uuid = await nodo.import('uuid');
+      return await uuid.v4()
+    }
+  JS
+end
+```
+
+Note that the availability of dynamic imports depends on your Node version.
+
 ### Alternate function definition syntax
 
 JS code can also be supplied using the `code:` keyword argument:

lib/nodo/nodo.js

@@ -9,7 +9,7 @@ module.exports = (function() {
   const path = require('path');
   const fs = require('fs');
   const performance = require('perf_hooks').performance;
-  
+
   let server, closing;
   const classes = {};
   const contexts = {};
@@ -48,7 +48,11 @@ module.exports = (function() {
       console.log(`[Nodo] ${message}`);
     }
   }
-
+
+  async function import_module(specifier) {
+    return await import(specifier);
+  }
+
   const core = {
     run: (socket) => {
       debug('Starting up...');
@@ -135,5 +139,5 @@ module.exports = (function() {
     }
   };
 
-  return { core: core, debug: debug };
+  return { core: core, debug: debug, import: import_module };
 })();

test/nodo_test.rb

@@ -224,13 +224,13 @@ def test_evaluation_can_require_on_its_own
     nodo = Class.new(Nodo::Core).new
     nodo.evaluate('const uuid = require("uuid")')
     uuid = nodo.evaluate('uuid.v4()')
-    assert_match /\A\w{8}-\w{4}-\w{4}-\w{4}-\w{12}\z/, uuid
+    assert_uuid uuid
   end
 
   def test_evaluation_can_access_requires
     nodo = Class.new(Nodo::Core) { require :uuid }
     uuid = nodo.new.evaluate('uuid.v4()')
-    assert_match /\A\w{8}-\w{4}-\w{4}-\w{4}-\w{12}\z/, uuid
+    assert_uuid uuid
   end
 
   def test_cannot_instantiate_core
@@ -239,6 +239,27 @@ def test_cannot_instantiate_core
     end
   end
 
+  def test_dynamic_imports_in_functions
+    klass = Class.new(Nodo::Core) do
+      function :v4, <<~JS
+        async () => {
+          const uuid = await nodo.import('uuid');
+          return await uuid.v4()
+        }
+      JS
+    end
+    nodo = klass.new
+    assert_uuid uuid_1 = nodo.v4
+    assert_uuid uuid_2 = nodo.v4
+    assert uuid_1 != uuid_2
+  end
+
+  def test_dynamic_imports_in_evaluation
+    nodo = Class.new(Nodo::Core)
+    uuid = nodo.new.evaluate("nodo.import('uuid').then((uuid) => uuid.v4()).catch((e) => null)")
+    assert_uuid uuid
+  end
+
   private
 
   def test_logger
@@ -256,5 +277,9 @@ def with_logger(logger)
   ensure
     Nodo.logger = prev_logger
   end
+
+  def assert_uuid(obj)
+    assert_match /\A\w{8}-\w{4}-\w{4}-\w{4}-\w{12}\z/, obj
+  end
 
 end