fix(plugin-helper): better handle content of TagNode

packages/bbob-plugin-helper/src/TagNode.js

@@ -5,7 +5,7 @@ class TagNode {
   constructor(tag, attrs, content) {
     this.tag = tag;
     this.attrs = attrs;
-    this.content = content;
+    this.content = [].concat(content);
   }
 
   attr(name, value) {

packages/bbob-plugin-helper/test/index.test.js

@@ -4,6 +4,7 @@ import {
   getNodeLength,
   isTagNode,
   isStringNode,
+  isEOL,
 } from '../src';
 
 describe('@bbob/plugin-helper', () => {
@@ -65,4 +66,8 @@ describe('@bbob/plugin-helper', () => {
 
     expect(attrValue('test', attrs)).toBe('test="{"tag":"test"}"');
   });
+
+  test('isEOL', () => {
+    expect(isEOL('\n')).toBe(true)
+  })
 });