feat(parser): Text#toHTML (#300)

Added support to render Text nodes as HTML for use in web applications.

src/parser/classes/misc/EmojiRun.ts

@@ -1,6 +1,7 @@
+import { escape, Run } from './Text';
 import Thumbnail from './Thumbnail';
 
-class EmojiRun {
+class EmojiRun implements Run {
   text: string;
   emoji: {
     emoji_id: string;
@@ -24,6 +25,15 @@ class EmojiRun {
       is_custom: !!data.emoji?.isCustomEmoji
     };
   }
+
+  toString() {
+    return this.text;
+  }
+
+  toHTML(): string {
+    const escaped_text = escape(this.text);
+    return `<img src="${this.emoji.image[0].url}" alt="${escaped_text}" title="${escaped_text}" style="display: inline-block; vertical-align: text-top; height: var(--yt-emoji-size, 1rem); width: var(--yt-emoji-size, 1rem);" loading="lazy" crossorigin="anonymous" />`;
+  }
 }
 
 export default EmojiRun;

src/parser/classes/misc/Text.ts

@@ -1,6 +1,21 @@
 import TextRun from './TextRun';
 import EmojiRun from './EmojiRun';
 
+export interface Run {
+  text: string;
+  toString(): string;
+  toHTML(): string;
+}
+
+export function escape(text: string) {
+  return text
+    .replace(/&/g, '&')
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;')
+    .replace(/"/g, '&quot;')
+    .replace(/'/g, '&#039;');
+}
+
 class Text {
   text: string;
   runs;
@@ -17,6 +32,10 @@ class Text {
     }
   }
 
+  toHTML() {
+    return this.runs ? this.runs.map((run) => run.toHTML()).join('') : this.text;
+  }
+
   toString() {
     return this.text;
   }

src/parser/classes/misc/TextRun.ts

@@ -1,6 +1,7 @@
 import NavigationEndpoint from '../NavigationEndpoint';
+import { escape, Run } from './Text';
 
-class TextRun {
+class TextRun implements Run {
   text: string;
   endpoint: NavigationEndpoint | undefined;
   bold: boolean;
@@ -14,6 +15,25 @@ class TextRun {
     this.strikethrough = Boolean(data.strikethrough);
     this.endpoint = data.navigationEndpoint ? new NavigationEndpoint(data.navigationEndpoint) : undefined;
   }
+
+  toString() {
+    return this.text;
+  }
+
+  toHTML(): string {
+    const tags: string[] = [];
+    if (this.bold) tags.push('b');
+    if (this.italics) tags.push('i');
+    if (this.strikethrough) tags.push('s');
+    const escaped_text = escape(this.text);
+    const styled_text = tags.map((tag) => `<${tag}>`).join('') + escaped_text + tags.map((tag) => `</${tag}>`).join('');
+    const wrapped_text = `<span style="white-space: pre-wrap;">${styled_text}</span>`;
+    if (this.endpoint) {
+      const url = this.endpoint.toURL();
+      if (url) return `<a href="${url}">${wrapped_text}</a>`;
+    }
+    return wrapped_text;
+  }
 }
 
 export default TextRun;