fix createWriteStream (#1433)

* fix createWriteStream

* remove comment

2 files changed, 104 insertions, 9 deletions

diff --git a/src/bun.js/fs.exports.js b/src/bun.js/fs.exports.js
index 019a98d6f..ebf929cb1 100644
--- a/src/bun.js/fs.exports.js
+++ b/src/bun.js/fs.exports.js
@@ -339,7 +339,6 @@ function getLazyReadStream() {
         callback();
         return;
       }
-      // this[readStreamPathFastPathSymbol] = false;
       var { path, flags, mode } = this;
 
       this.#fs.open(path, flags, mode, (er, fd) => {
@@ -625,7 +624,7 @@ function getLazyWriteStream() {
       this._writableState.autoDestroy = val;
     }
 
-    destroySoon = this.end;
+    destroySoon = this.end; // TODO: what is this for?
 
     // noop, node has deprecated this
     open() {}
@@ -696,6 +695,26 @@ function getLazyWriteStream() {
       });
     }
 
+    _construct(callback) {
+      if (typeof this.fd === "number") {
+        callback();
+        return;
+      }
+      var { path, flags, mode } = this;
+
+      this.#fs.open(path, flags, mode, (er, fd) => {
+        if (er) {
+          callback(er);
+          return;
+        }
+
+        this.fd = fd;
+        callback();
+        this.emit("open", this.fd);
+        this.emit("ready");
+      });
+    }
+
     _destroy(err, cb) {
       if (this.fd === null) {
         return cb(err);
@@ -745,7 +764,7 @@ function getLazyWriteStream() {
           chunk.length,
           this.pos,
           (err, bytes) => {
-            ths[kIoDone] = false;
+            this[kIoDone] = false;
             this.#handleWrite(err, bytes);
             this.emit(kIoDone);
 
@@ -754,12 +773,19 @@ function getLazyWriteStream() {
         );
       } else {
         this[kIoDone] = true;
-        this.#fs.write(this.fd, chunk, 0, chunk.length, null, (err, bytes) => {
-          ths[kIoDone] = false;
-          this.#handleWrite(err, bytes);
-          this.emit(kIoDone);
-          !err ? cb() : cb(err);
-        });
+        this.#fs.write(
+          this.fd,
+          chunk,
+          0,
+          chunk.length,
+          null,
+          (err, bytes, buffer) => {
+            this[kIoDone] = false;
+            this.#handleWrite(err, bytes);
+            this.emit(kIoDone);
+            !err ? cb() : cb(err);
+          }
+        );
       }
     }
     _write = this.#internalWrite;
diff --git a/test/bun.js/fs.test.js b/test/bun.js/fs.test.js
index e2d305f01..3976ba372 100644
--- a/test/bun.js/fs.test.js
+++ b/test/bun.js/fs.test.js
@@ -16,6 +16,7 @@ import {
   copyFileSync,
   rmSync,
   createReadStream,
+  createWriteStream,
 } from "node:fs";
 import { join } from "node:path";
 
@@ -462,3 +463,71 @@ describe("createReadStream", () => {
     });
   });
 });
+
+describe("createWriteStream", () => {
+  it("simple write stream finishes", async () => {
+    const path = `/tmp/fs.test.js/${Date.now()}.createWriteStream.txt`;
+    const stream = createWriteStream(path);
+    stream.write("Test file written successfully");
+    stream.end();
+
+    return await new Promise((resolve, reject) => {
+      stream.on("error", (e) => {
+        reject(e);
+      });
+
+      stream.on("finish", () => {
+        expect(readFileSync(path, "utf8")).toBe(
+          "Test file written successfully"
+        );
+        resolve(true);
+      });
+    });
+  });
+
+  it("writing null throws ERR_STREAM_NULL_VALUES", async () => {
+    const path = `/tmp/fs.test.js/${Date.now()}.createWriteStreamNulls.txt`;
+    const stream = createWriteStream(path);
+    try {
+      stream.write(null);
+      throw new Error("should not get here");
+    } catch (exception) {
+      expect(exception.code).toBe("ERR_STREAM_NULL_VALUES");
+    }
+  });
+
+  it("writing null with objectMode: true throws ERR_STREAM_NULL_VALUES", async () => {
+    const path = `/tmp/fs.test.js/${Date.now()}.createWriteStreamNulls.txt`;
+    const stream = createWriteStream(path, {
+      objectMode: true,
+    });
+    try {
+      stream.write(null);
+      throw new Error("should not get here");
+    } catch (exception) {
+      expect(exception.code).toBe("ERR_STREAM_NULL_VALUES");
+    }
+  });
+
+  it("writing false throws ERR_INVALID_ARG_TYPE", async () => {
+    const path = `/tmp/fs.test.js/${Date.now()}.createWriteStreamFalse.txt`;
+    const stream = createWriteStream(path);
+    try {
+      stream.write(false);
+      throw new Error("should not get here");
+    } catch (exception) {
+      expect(exception.code).toBe("ERR_INVALID_ARG_TYPE");
+    }
+  });
+
+  it("writing false with objectMode: true should not throw", async () => {
+    const path = `/tmp/fs.test.js/${Date.now()}.createWriteStreamFalse.txt`;
+    const stream = createWriteStream(path, {
+      objectMode: true,
+    });
+    stream.write(false);
+    stream.on("error", () => {
+      throw new Error("should not get here");
+    });
+  });
+});