fix: remove node dependencies for esm bundle, see #173

rollup.config.ts

@@ -43,7 +43,18 @@ const esm = {
     banner
   }],
   external: ['path', 'fs'],
-  plugins: [typescript({
+  plugins: [
+    replace({
+      include: './src/liquid.ts',
+      delimiters: ['', ''],
+      './fs/node': './fs/browser'
+    }),
+    replace({
+      include: './src/parser/tokenizer.ts',
+      delimiters: ['', ''],
+      './flatten/node': './flatten/browser'
+    }),
+    typescript({
       tsconfigOverride: {
         include: [ 'src' ],
         exclude: [ 'test', 'benchmark' ],
@@ -52,7 +63,8 @@ const esm = {
           module: 'ES2015'
         }
       }
-  })],
+    })
+  ],
   treeshake,
   input
 }