initial commit

src/sources/FileSource.ts

@@ -0,0 +1,38 @@
+import type { IChunkSource } from "../types";
+
+export class FileChunkSource implements IChunkSource {
+  private readonly path: string;
+  private readonly chunkSize: number;
+
+  public constructor(path: string, chunkSize: number = 64 * 1024) {
+    this.path = path;
+    this.chunkSize = Math.max(1024, chunkSize);
+  }
+
+  public async *chunks(): AsyncIterable<string> {
+    // Prefer Bun if available; fall back to Node streams to keep portability
+    if (typeof Bun !== "undefined" && typeof Bun.file === "function") {
+      const file = Bun.file(this.path);
+      const reader = file.stream().getReader();
+      try {
+        while (true) {
+          const { value, done } = await reader.read();
+          if (done) break;
+          if (value) yield Buffer.from(value).toString("utf8");
+        }
+      } finally {
+        reader.releaseLock();
+      }
+      return;
+    }
+
+    // Node.js fallback
+    const { createReadStream } = await import("node:fs");
+    const stream = createReadStream(this.path, { encoding: "utf8", highWaterMark: this.chunkSize });
+    for await (const chunk of stream) {
+      yield chunk as string;
+    }
+  }
+}
+
+