Add shared library for APIs/chunking

lib/voyage.js

@@ -0,0 +1,66 @@
+const VOYAGE_API_URL = "https://api.voyageai.com/v1";
+const EMBED_MODEL = "voyage-3";
+const RERANK_MODEL = "rerank-2";
+const EMBED_BATCH_SIZE = 32;
+
+function getApiKey() {
+    const key = process.env.VOYAGE_API_KEY;
+    if (!key) throw new Error("VOYAGE_API_KEY is not set");
+    return key;
+}
+
+async function voyagePost(path, body) {
+    const res = await fetch(`${VOYAGE_API_URL}${path}`, {
+        method: "POST",
+        headers: {
+            "Content-Type": "application/json",
+            Authorization: `Bearer ${getApiKey()}`,
+        },
+        body: JSON.stringify(body),
+    });
+
+    if (!res.ok) {
+        const text = await res.text();
+        throw new Error(`Voyage ${path} failed (${res.status}): ${text}`);
+    }
+
+    return res.json();
+}
+
+// Embed text -  voyage-3. inputType must be "document" (ingest) or "query" (search).
+
+export async function embedTexts(texts, inputType = "document") {
+    if (texts.length === 0) return [];
+
+    const embeddings = [];
+    for (let i = 0; i < texts.length; i += EMBED_BATCH_SIZE) {
+        const batch = texts.slice(i, i + EMBED_BATCH_SIZE);
+        const json = await voyagePost("/embeddings", {
+            model: EMBED_MODEL,
+            input: batch,
+            input_type: inputType,
+        });
+        const ordered = (json.data || [])
+            .slice()
+            .sort((a, b) => (a.index ?? 0) - (b.index ?? 0));
+        embeddings.push(...ordered.map((d) => d.embedding));
+    }
+    return embeddings;
+}
+
+export async function rerank(query, documents) {
+    if (!documents || documents.length === 0) return [];
+
+    const texts = documents.map((d) => (typeof d === "string" ? d : d.text));
+    const json = await voyagePost("/rerank", {
+        model: RERANK_MODEL,
+        query,
+        documents: texts,
+    });
+
+    return (json.data || []).map((item) => ({
+        index: item.index,
+        document: documents[item.index],
+        relevanceScore: item.relevance_score,
+    }));
+}