fix(csv/csv_stringify_stream): output headers based on columns opti…

…on (#3293)
denoland · Mar 30, 2023 · 87f4a8b · 87f4a8b
1 parent f980ab9
commit 87f4a8b
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diff --git a/csv/csv_stringify_stream.ts b/csv/csv_stringify_stream.ts
@@ -52,6 +52,17 @@ export class CsvStringifyStream<TOptions extends CsvStringifyStreamOptions>
 
     super(
       {
+        start(controller) {
+          if (columns && columns.length > 0) {
+            try {
+              controller.enqueue(
+                stringify([columns], { separator, headers: false }),
+              );
+            } catch (error) {
+              controller.error(error);
+            }
+          }
+        },
         transform(chunk, controller) {
           try {
             controller.enqueue(

diff --git a/csv/csv_stringify_stream_test.ts b/csv/csv_stringify_stream_test.ts
@@ -89,6 +89,7 @@ Deno.test({
         output.push(r);
       }
       assertEquals(output, [
+        "id,name\r\n",
         "1,foo\r\n",
         "2,bar\r\n",
         "3,baz\r\n",