1 files changed, 76 insertions, 0 deletions
diff --git a/cli/js/write_file.ts b/cli/js/write_file.ts
new file mode 100644
index 000000000..d6307e002
--- /dev/null
+++ b/cli/js/write_file.ts
@@ -0,0 +1,76 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { stat, statSync } from "./stat.ts";
+import { open, openSync } from "./files.ts";
+import { chmod, chmodSync } from "./chmod.ts";
+import { writeAll, writeAllSync } from "./buffer.ts";
+
+/** Options for writing to a file.
+ * `perm` would change the file's permission if set.
+ * `create` decides if the file should be created if not exists (default: true)
+ * `append` decides if the file should be appended (default: false)
+ */
+export interface WriteFileOptions {
+  perm?: number;
+  create?: boolean;
+  append?: boolean;
+}
+
+/** Write a new file, with given filename and data synchronously.
+ *
+ *       const encoder = new TextEncoder();
+ *       const data = encoder.encode("Hello world\n");
+ *       Deno.writeFileSync("hello.txt", data);
+ */
+export function writeFileSync(
+  filename: string,
+  data: Uint8Array,
+  options: WriteFileOptions = {}
+): void {
+  if (options.create !== undefined) {
+    const create = !!options.create;
+    if (!create) {
+      // verify that file exists
+      statSync(filename);
+    }
+  }
+
+  const openMode = !!options.append ? "a" : "w";
+  const file = openSync(filename, openMode);
+
+  if (options.perm !== undefined && options.perm !== null) {
+    chmodSync(filename, options.perm);
+  }
+
+  writeAllSync(file, data);
+  file.close();
+}
+
+/** Write a new file, with given filename and data.
+ *
+ *       const encoder = new TextEncoder();
+ *       const data = encoder.encode("Hello world\n");
+ *       await Deno.writeFile("hello.txt", data);
+ */
+export async function writeFile(
+  filename: string,
+  data: Uint8Array,
+  options: WriteFileOptions = {}
+): Promise<void> {
+  if (options.create !== undefined) {
+    const create = !!options.create;
+    if (!create) {
+      // verify that file exists
+      await stat(filename);
+    }
+  }
+
+  const openMode = !!options.append ? "a" : "w";
+  const file = await open(filename, openMode);
+
+  if (options.perm !== undefined && options.perm !== null) {
+    await chmod(filename, options.perm);
+  }
+
+  await writeAll(file, data);
+  file.close();
+}