diff --git a/src/index.ts b/src/index.ts
index fff528e..16a2afc 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -24,6 +24,15 @@ export function toString(node: MfmNode | MfmNode[]): string {
 	}
 }
 
+export function inspect(tree: MfmNode[], action: (node: MfmNode) => void): void {
+	for (const node of tree) {
+		action(node);
+		if (node.children != null) {
+			inspect(node.children, action);
+		}
+	}
+}
+
 export {
 	MfmNode,
 	MfmBlock,
diff --git a/test/main.ts b/test/main.ts
index 49555f5..8aabd05 100644
--- a/test/main.ts
+++ b/test/main.ts
@@ -1,5 +1,5 @@
 import assert from 'assert';
-import { parse, parsePlain } from '../built/index';
+import { inspect, parse, parsePlain, toString } from '../built/index';
 import { createNode } from '../built/util';
 import {
 	TEXT, CENTER, FN, UNI_EMOJI, MENTION, CUSTOM_EMOJI, HASHTAG, N_URL, BOLD, SMALL, ITALIC, STRIKE, QUOTE
@@ -401,3 +401,16 @@ https://github.com/syuilo/ai
 	];
 	assert.deepStrictEqual(parse(input), output);
 });
+
+describe('inspect', () => {
+	it('replace text', () => {
+		const input = 'good morning [tada everynyan!]';
+		const result = parse(input);
+		inspect(result, node => {
+			if (node.type == 'text') {
+				node.props.text = node.props.text.replace(/good morning/g, 'hello');
+			}
+		});
+		assert.strictEqual(toString(result), 'hello [tada everynyan!]');
+	});
+});