Make dependencies parsing optional (#19)

* Handle `xml2js` import error
* Fix workflow for JS changes
* Fix linter settings

.eslintrc.js

@@ -7,7 +7,7 @@ module.exports = {
     },
     "extends": "eslint:recommended",
     "parserOptions": {
-        "ecmaVersion": 9,
+        "ecmaVersion": 11,
         "sourceType": "module"
     },
     "rules": {

.github/workflows/tests.yml

@@ -7,6 +7,7 @@ on:
     branches: [ master ]
     paths:
       - '*.js'
+      - 'src/*'
       - 'test/*'
       - 'package.json'
 

src/get-dependencies.js

@@ -1,7 +1,7 @@
 import path from 'path';
 import fs from 'fs';
 import util from 'util';
-import {parseStringPromise} from 'xml2js';
+import {getParser} from './get-parser';
 import {NODE_ATTRIBUTES} from './nodes';
 import {filterNodes} from './filter-nodes';
 
@@ -24,7 +24,7 @@ function getSrcAttribute({item: [attributes]}) {
  * @return {Promise<Set<string>>}
  */
 async function getFileImports(source) {
-    const root = await parseStringPromise(source);
+    const root = await getParser().then((parseString) => parseString(source));
     const nodes = filterNodes(root, [
         'fest:include',
         'fest:insert'

src/get-parser.js

@@ -0,0 +1,5 @@
+export function getParser() {
+    return import('xml2js').then(function({parseStringPromise}) {
+        return parseStringPromise;
+    });
+}