Fix utils.warn usage in strict mode.

.gitignore

@@ -1,3 +1,4 @@
 /node_modules
 docs/
 test/env/file_list.json
+build/lunr.temp.js

Makefile

@@ -39,7 +39,9 @@ release: lunr.js lunr.min.js bower.json package.json component.json docs
 lunr.js: $(SRC)
 	cat build/wrapper_start $^ build/wrapper_end | \
 	sed "s/@YEAR/${YEAR}/" | \
-	sed "s/@VERSION/${VERSION}/" > $@
+	sed "s/@VERSION/${VERSION}/" > \
+	build/lunr.temp.js
+	npx rollup --input build/lunr.temp.js --config build/rollup.config.js
 
 lunr.min.js: lunr.js
 	${UGLIFYJS} --compress --mangle --comments < $< > $@
@@ -80,6 +82,7 @@ clean:
 	rm -f lunr{.min,}.js
 	rm -rf docs
 	rm *.json
+	rm -f build/lunr.temp.js
 
 reset:
 	git checkout lunr.* *.json

build/rollup.config.js

@@ -0,0 +1,15 @@
+
+export default {
+  input: 'lunr.js',
+  output: [
+    {
+      file: 'lunr.js',
+      format: 'umd',
+      name: 'lunr'
+    },
+    {
+      file: 'lunr.es6.js',
+      format: 'esm'
+    }
+  ]
+};

build/wrapper_end

@@ -1,29 +1,2 @@
 
-  /**
-   * export the module via AMD, CommonJS or as a browser global
-   * Export code from https://github.com/umdjs/umd/blob/master/returnExports.js
-   */
-  ;(function (root, factory) {
-    if (typeof define === 'function' && define.amd) {
-      // AMD. Register as an anonymous module.
-      define(factory)
-    } else if (typeof exports === 'object') {
-      /**
-       * Node. Does not work with strict CommonJS, but
-       * only CommonJS-like enviroments that support module.exports,
-       * like Node.
-       */
-      module.exports = factory()
-    } else {
-      // Browser globals (root is window)
-      root.lunr = factory()
-    }
-  }(this, function () {
-    /**
-     * Just return a value to define the module export.
-     * This example returns an object, but the module
-     * can return a function as the exported value.
-     */
-    return lunr
-  }))
-})();
+export default lunr;

build/wrapper_start

@@ -4,5 +4,3 @@
  * @license MIT
  */
 
-;(function(){
-

lib/utils.js

@@ -16,15 +16,13 @@ lunr.utils = {}
  * @memberOf lunr.utils
  * @function
  */
-lunr.utils.warn = (function (global) {
+lunr.utils.warn = function (message) {
   /* eslint-disable no-console */
-  return function (message) {
-    if (global.console && console.warn) {
+    if ((typeof console !== 'undefined') && console.warn) {
       console.warn(message)
     }
-  }
   /* eslint-enable no-console */
-})(this)
+}
 
 /**
  * Convert an object to a string.