diff --git a/.travis.yml b/.travis.yml
index 9d2f2e21..7147325b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,7 @@ before_install:
     - git submodule update --init --recursive
 language: node_js
 node_js:
-  - "10.16.0"
+  - "14.3.0"
 script:
   - npm run build
   - npm test
diff --git a/src/worker/workermain.ts b/src/worker/workermain.ts
index 7ddd9ff4..d71e27e5 100644
--- a/src/worker/workermain.ts
+++ b/src/worker/workermain.ts
@@ -10,13 +10,11 @@ const emglobal : any = this['window'] || this['global'] || this;
 const ENVIRONMENT_IS_WEB = typeof window === 'object';
 const ENVIRONMENT_IS_WORKER = typeof importScripts === 'function';
 
-//const self = emglobal.self;
-//const __WORKER__ = function() {
-
 // WebAssembly module cache
 // TODO: leaks memory even when disabled...
 var _WASM_module_cache = {};
-var CACHE_WASM_MODULES = true;
+var CACHE_WASM_MODULES = true; // if false, use asm.js only
+
 function getWASMModule(module_id:string) {
   var module = _WASM_module_cache[module_id];
   if (!module) {
diff --git a/test/cli/testworker.js b/test/cli/testworker.js
index 36a9cfc8..6993d9b4 100644
--- a/test/cli/testworker.js
+++ b/test/cli/testworker.js
@@ -4,9 +4,6 @@ var fs = require('fs');
 var wtu = require('./workertestutils.js');
 //var heapdump = require('heapdump');
 
-// TODO: why memory leak?
-CACHE_WASM_MODULES = false;
-
 global.onmessage({data:{preload:'cc65', platform:'nes'}});
 global.onmessage({data:{preload:'ca65', platform:'nes'}});
 global.onmessage({data:{preload:'cc65', platform:'apple2'}});
diff --git a/test/cli/workertestutils.js b/test/cli/workertestutils.js
index 251e8979..47814580 100644
--- a/test/cli/workertestutils.js
+++ b/test/cli/workertestutils.js
@@ -7,6 +7,13 @@ var worker = {};
 
 global.window = global;
 global.exports = {};
+global.self = global;
+global.location = {href:'.'};
+global.require = (modname) => {
+  console.log("REQUIRE",modname);
+  if (modname == 'path')
+    return require(modname);
+};
 
 global.btoa = require('btoa');
 global.atob = require('atob');