From fde54310964a20373e5db991c7dcfd90951b048e Mon Sep 17 00:00:00 2001
From: Aleksandr Dukhovnyy <script@vip-person.net>
Date: Mon, 3 Oct 2022 14:20:03 +0300
Subject: [PATCH] initial commit

---
 README.MD    | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 index.js     | 51 +++++++++++++++++++++++++++++++++++++++++++++
 package.json | 26 +++++++++++++++++++++++
 3 files changed, 136 insertions(+)
 create mode 100644 README.MD
 create mode 100644 index.js
 create mode 100644 package.json

diff --git a/README.MD b/README.MD
new file mode 100644
index 0000000..32e98fc
--- /dev/null
+++ b/README.MD
@@ -0,0 +1,59 @@
+# purify-html
+
+![size](https://img.shields.io/github/languages/code-size/Aleksandr-JS-Developer/purify-html?style=flat-square)
+
+A minimalistic library for sanitizing strings so that they can be safely used as HTML.
+
+The main idea is to use the browser API to parse, parse and modify the DOM.
+
+## Install
+
+```bash
+npm install purify-html
+```
+
+## Usage
+
+```javascript
+import Sanitizer from 'purify-html';
+
+const allowedTags = [
+  { name: 'br' },
+  { name: 'b', attributes: ['class'] },
+  { name: 'p', attributes: ['data-some'] },
+];
+
+const sanitizer = new Sanitizer(allowedTags);
+
+const dangerString = `
+  <script> fetch('google.com', { mode: 'no-cors' }) </script>
+
+  <<div></div>img src="1" onerror="alert(1)">
+  <img src="1" onerror="alert(1)">
+
+  <b>Bold</b>
+  <b class="red">Bold</b>
+  <b class="red" onclick="alert(1)">Bold</b>
+  <p data-some="123" data-some-else="321">123</p>
+  <div></div>
+`;
+
+const safeString = sanitizer.sanitize(dangerString);
+
+console.log(safeString);
+
+/*
+  &lt;img src="1" onerror="alert(1)"&gt;
+  
+
+  <b>Bold</b>
+  <b class="red">Bold</b>
+  <b class="red">Bold</b>
+  <p data-some="123">123</p>
+
+*/
+```
+
+## Browser support
+
+Although browser support is already over 95%, the specification for DOMParser is not yet fully established. [More details](https://caniuse.com/mdn-api_domparser_parsefromstring_html).
diff --git a/index.js b/index.js
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+++ b/index.js
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+class Sanitizer {
+  constructor(allowedTags = []) {
+    this.allowedTags = allowedTags.reduce((acc, curr) => {
+      const name = curr.name;
+      delete curr.name;
+
+      acc[name] = curr;
+
+      return acc;
+    }, {});
+    this.whiteList = Object.keys(this.allowedTags);
+
+    this.sanitize.bind(this);
+  }
+  sanitize(str) {
+    const wrapper = new DOMParser()
+      .parseFromString(str, 'text/html')
+      .querySelector('body');
+
+    const allItems = wrapper.querySelectorAll('*');
+
+    allItems.forEach((tag) => {
+      const name = tag.tagName.toLowerCase();
+
+      if (this.whiteList.includes(name)) {
+        const tagConfig = this.allowedTags[name];
+
+        if (tagConfig.attributes !== undefined) {
+          for (let i = 0; i < tag.attributes.length; i++) {
+            const attr = tag.attributes[i];
+
+            if (!tagConfig.attributes.includes(attr.name)) {
+              tag.removeAttribute(attr.name);
+            }
+          }
+        } else {
+          for (let i = 0; i < tag.attributes.length; i++) {
+            tag.removeAttribute(tag.attributes[i].name);
+          }
+        }
+      } else {
+        tag.insertAdjacentHTML('afterend', this.sanitize(tag.innerHTML));
+        tag.remove();
+      }
+    });
+
+    return wrapper.innerHTML;
+  }
+}
+
+module.exports = Sanitizer;
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..dbea121
--- /dev/null
+++ b/package.json
@@ -0,0 +1,26 @@
+{
+  "name": "purify-html",
+  "version": "1.0.1",
+  "description": "A minimalistic library for sanitizing strings so that they can be safely used as HTML.",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/Aleksandr-JS-Developer/purify-html.git"
+  },
+  "keywords": [
+    "html-sanitize",
+    "sanitize"
+  ],
+  "author": "alex-js-dev",
+  "license": "MIT",
+  "files": [
+    "index.js"
+  ],
+  "bugs": {
+    "url": "https://github.com/Aleksandr-JS-Developer/purify-html/issues"
+  },
+  "homepage": "https://github.com/Aleksandr-JS-Developer/purify-html#readme"
+}