Add enhanced Markdown to LinkedIn conversion and X thread splitter

src/thread-splitter.ts

@@ -0,0 +1,174 @@
+export interface ThreadOptions {
+    maxChars: number;
+    addNumbering: boolean;
+}
+
+const DEFAULT_OPTIONS: ThreadOptions = {
+    maxChars: 280,
+    addNumbering: true,
+};
+
+const NUMBERING_RESERVE = 8;
+
+function countChars(text: string): number {
+    let count = 0;
+    let lastIndex = 0;
+    const urlRe = /https?:\/\/\S+/g;
+    let match: RegExpExecArray | null;
+
+    while ((match = urlRe.exec(text)) !== null) {
+        count += match.index - lastIndex;
+        count += 23;
+        lastIndex = urlRe.lastIndex;
+    }
+    count += text.length - lastIndex;
+    return count;
+}
+
+function textFits(text: string, max: number): boolean {
+    return countChars(text) <= max;
+}
+
+function splitByWords(text: string, max: number): string[] {
+    const words = text.split(/\s+/);
+    const chunks: string[] = [];
+    let current = "";
+
+    for (const word of words) {
+        if (!current) {
+            current = word;
+            continue;
+        }
+        const candidate = current + " " + word;
+        if (countChars(candidate) <= max - 3) {
+            current = candidate;
+        } else {
+            chunks.push(current + "...");
+            current = word;
+        }
+    }
+
+    if (current) chunks.push(current);
+    return chunks;
+}
+
+function splitBySentences(text: string, max: number): string[] {
+    const sentences = text.match(/[^.!?\s][^.!?]*(?:[.!?]+|$)/g) || [text];
+    const chunks: string[] = [];
+    let current = "";
+
+    for (const sentence of sentences) {
+        if (!current) {
+            if (textFits(sentence, max)) {
+                current = sentence;
+            } else {
+                chunks.push(...splitByWords(sentence, max));
+            }
+        } else {
+            const candidate = current + sentence;
+            if (textFits(candidate, max)) {
+                current = candidate;
+            } else {
+                chunks.push(current);
+                if (textFits(sentence, max)) {
+                    current = sentence;
+                } else {
+                    chunks.push(...splitByWords(sentence, max));
+                    current = "";
+                }
+            }
+        }
+    }
+
+    if (current) chunks.push(current);
+    return chunks;
+}
+
+function splitBlock(text: string, max: number): string[] {
+    const lines = text.split("\n").filter(l => l.trim());
+    const chunks: string[] = [];
+    let current = "";
+
+    for (const line of lines) {
+        const trimmed = line.trim();
+        if (!current) {
+            if (textFits(trimmed, max)) {
+                current = trimmed;
+            } else {
+                chunks.push(...splitBySentences(trimmed, max));
+            }
+        } else {
+            const candidate = current + "\n" + trimmed;
+            if (textFits(candidate, max)) {
+                current = candidate;
+            } else {
+                chunks.push(current);
+                if (textFits(trimmed, max)) {
+                    current = trimmed;
+                } else {
+                    chunks.push(...splitBySentences(trimmed, max));
+                    current = "";
+                }
+            }
+        }
+    }
+
+    if (current) chunks.push(current);
+    return chunks.length > 0 ? chunks : [text];
+}
+
+export function splitIntoThreads(text: string, options?: Partial<ThreadOptions>): string[] {
+    const opts: ThreadOptions = Object.assign({}, DEFAULT_OPTIONS, options);
+    const effectiveMax = opts.addNumbering ? opts.maxChars - NUMBERING_RESERVE : opts.maxChars;
+    const paragraphs = text.split(/\n{2,}/).filter(p => p.trim());
+
+    if (paragraphs.length === 0) return [];
+
+    const rawTweets: string[] = [];
+    let current = "";
+
+    for (const para of paragraphs) {
+        const trimmed = para.trim();
+
+        if (!current) {
+            if (textFits(trimmed, effectiveMax)) {
+                current = trimmed;
+            } else {
+                const chunks = splitBlock(trimmed, effectiveMax);
+                if (chunks.length > 1) {
+                    rawTweets.push(...chunks.slice(0, -1));
+                    current = chunks[chunks.length - 1]!;
+                } else {
+                    current = chunks[0]!;
+                }
+            }
+        } else {
+            const candidate = current + "\n\n" + trimmed;
+            if (textFits(candidate, effectiveMax)) {
+                current = candidate;
+            } else {
+                rawTweets.push(current);
+                if (textFits(trimmed, effectiveMax)) {
+                    current = trimmed;
+                } else {
+                    const chunks = splitBlock(trimmed, effectiveMax);
+                    if (chunks.length > 1) {
+                        rawTweets.push(...chunks.slice(0, -1));
+                        current = chunks[chunks.length - 1]!;
+                    } else {
+                        current = chunks[0]!;
+                    }
+                }
+            }
+        }
+    }
+
+    if (current) rawTweets.push(current);
+
+    if (opts.addNumbering && rawTweets.length > 1) {
+        const total = rawTweets.length;
+        return rawTweets.map((tweet, i) => `${i + 1}/${total} ${tweet}`);
+    }
+
+    return rawTweets;
+}