fix(csv-generate): preserve eof after an overflowing final record

packages/csv-generate/lib/api/read.js

@@ -25,7 +25,13 @@ const read = (options, state, size, push, close) => {
       (options.duration && Date.now() > state.start_time + options.duration)
     ) {
       // Flush
-      if (data.length) {
+      if (
+        data.length ||
+        (!options.objectMode &&
+          options.eof &&
+          state.count_created > 0 &&
+          state.end !== true)
+      ) {
         if (options.objectMode) {
           for (const record of data) {
             push(record);

packages/csv-generate/test/options.eof.js

@@ -1,7 +1,81 @@
 import "should";
 import { generate } from "../lib/index.js";
+import { generate as generateSync } from "../lib/sync.js";
+import { generate as generateStream } from "../lib/stream.js";
 
 describe("Option `eof`", function () {
+  it("preserves a custom suffix after an overflowing final record", function (next) {
+    generate(
+      {
+        columns: [() => "xx"],
+        length: 2,
+        highWaterMark: 3,
+        eof: "END",
+      },
+      (err, data) => {
+        if (err) return next(err);
+        data.toString().should.eql("xx\nxxEND");
+        next();
+      },
+    );
+  });
+
+  it("emits eof once across synchronous read boundaries", function () {
+    for (const highWaterMark of [1, 2, 3, 4, 5, 6]) {
+      for (const fixed_size of [false, true]) {
+        generateSync({
+          columns: [() => "xx"],
+          length: 2,
+          highWaterMark,
+          fixed_size,
+          eof: "END",
+        }).should.eql("xx\nxxEND");
+      }
+    }
+  });
+
+  it("preserves a custom row delimiter as eof in streamed output", async function () {
+    const chunks = [];
+    for await (const chunk of generate({
+      columns: [() => "xx"],
+      length: 1,
+      highWaterMark: 1,
+      row_delimiter: "\r\n",
+      eof: true,
+      sleep: 1,
+    })) {
+      chunks.push(chunk);
+    }
+    Buffer.concat(chunks).toString().should.eql("xx\r\n");
+  });
+
+  it("preserves eof after overflowing a web stream read", async function () {
+    const field = "x".repeat(1024);
+    const chunks = [];
+    for await (const chunk of generateStream({
+      columns: [() => field],
+      length: 2,
+      eof: "END",
+    })) {
+      chunks.push(chunk);
+    }
+    Buffer.concat(chunks).toString().should.eql(`${field}\n${field}END`);
+  });
+
+  it("leaves empty output empty", function () {
+    generateSync({ length: 0, eof: "END" }).should.eql("");
+  });
+
+  it("does not append eof to object records", function () {
+    generateSync({
+      columns: [() => "xx"],
+      length: 1,
+      objectMode: true,
+      highWaterMark: 1,
+      eof: "END",
+    }).should.eql([["xx"]]);
+  });
+
   it("default to trailing newline character if true", function (next) {
     generate(
       {