chore(core): string node walk plugin test

packages/bbob-core/README.md

@@ -3,12 +3,12 @@
 ## Usage
 
 ```js
-const bbob = require('@bbob/core');
-const render = require('@bbob/html');
-const presetHTML5 = require('@bbob/preset-html5');
+import bbob from '@bbob/core'
+import { render } from '@bbob/html'
+import presetHTML5 from '@bbob/preset-html5'
 const code = `[i]Text[/i]`;
 
-const html = bbob([presetHTML5()]).process(code, { render }).html;
+const html = bbob(presetHTML5()).process(code, { render }).html;
 
 console.log(html); // <span style="font-style: italic;">Text</span>
 ```

packages/bbob-core/src/index.js

@@ -19,6 +19,10 @@ export default function bbob(plugs) {
       const parseFn = options.parser || parse;
       const renderFn = options.render;
 
+      if (typeof parseFn !== 'function') {
+        throw new Error('"parser" is not a function, please pass to "process(input, { parser })" right function');
+      }
+
       let tree = options.skipParse
         ? input || []
         : parseFn(input, options);

packages/bbob-core/test/index.test.js

@@ -1,4 +1,5 @@
 import render from '@bbob/html'
+import { TagNode } from '@bbob/parser'
 import core from '../src'
 
 const stringify = val => JSON.stringify(val);
@@ -21,7 +22,7 @@ describe('@bbob/core', () => {
     ]))
   });
 
-  test('plugin walk api', () => {
+  test('plugin walk api node', () => {
     const testPlugin = () => (tree) => tree.walk(node => {
       if (node.tag === 'mytag') {
         node.attrs = {
@@ -55,6 +56,38 @@ describe('@bbob/core', () => {
     ]));
   });
 
+  test('plugin walk api string', () => {
+    const testPlugin = () => (tree) => tree.walk(node => {
+      if (node === ':)') {
+        return TagNode.create('test-tag')
+      }
+
+      return node
+    });
+
+    const res = process([testPlugin()], '[mytag]Large Text :)[/mytag]');
+    const ast = res.tree;
+
+    expect(ast).toBeInstanceOf(Array);
+    expect(ast.walk).toBeInstanceOf(Function);
+    expect(stringify(ast)).toEqual(stringify([
+      {
+        tag: 'mytag',
+        attrs: {},
+        content: [
+          'Large',
+          ' ',
+          'Text',
+          {
+            tag: 'test-tag',
+            attrs: {},
+            content: [],
+          }
+        ]
+      }
+    ]));
+  });
+
   test('plugin match api', () => {
     const testPlugin = () => (tree) => tree.match([{ tag: 'mytag1' }, { tag: 'mytag2' }], node => {
       if (node.attrs) {