feat(csv-parse): implement TransformStream

packages/csv-parse/dist/esm/stream.d.ts

@@ -0,0 +1,11 @@
+
+import { Options } from './index.js';
+
+declare function parse(options?: Options): TransformStream;
+// export default parse;
+export { parse };
+
+export {
+  CastingContext, CastingFunction, CastingDateFunction,
+  ColumnOption, Options, Info, CsvErrorCode, CsvError
+} from './index.js';

packages/csv-parse/lib/stream.d.ts

@@ -0,0 +1,11 @@
+
+import { Options } from './index.js';
+
+declare function parse(options?: Options): TransformStream;
+// export default parse;
+export { parse };
+
+export {
+  CastingContext, CastingFunction, CastingDateFunction,
+  ColumnOption, Options, Info, CsvErrorCode, CsvError
+} from './index.js';

packages/csv-parse/lib/stream.js

@@ -1,34 +1,40 @@
-import { TransformStream } from "node:stream/web";
+import { TransformStream, CountQueuingStrategy } from "node:stream/web";
 import { transform } from "./api/index.js";
 
 const parse = (opts) => {
   const api = transform(opts);
-  return new TransformStream({
-    async transform(chunk, controller) {
-      api.parse(
-        chunk,
-        false,
-        (record) => {
-          controller.enqueue(record);
-        },
-        () => {
-          controller.close();
-        },
-      );
-    },
-    async flush(controller) {
-      api.parse(
-        undefined,
-        true,
-        (record) => {
-          controller.enqueue(record);
-        },
-        () => {
-          controller.close();
-        },
-      );
+  let controller;
+  const enqueue = (record) => {
+    controller.enqueue(record);
+  };
+  const terminate = () => {
+    controller.terminate();
+  };
+  return new TransformStream(
+    {
+      start(ctr) {
+        controller = ctr;
+      },
+      transform(chunk) {
+        const error = api.parse(chunk, false, enqueue, terminate);
+
+        if (error) {
+          controller.error(error);
+          throw error;
+        }
+      },
+      flush() {
+        const error = api.parse(undefined, true, enqueue, terminate);
+
+        if (error) {
+          controller.error(error);
+          throw error;
+        }
+      },
     },
-  });
+    new CountQueuingStrategy({ highWaterMark: 1024 }),
+    new CountQueuingStrategy({ highWaterMark: 1024 }),
+  );
 };
 
 export { parse };

packages/csv-parse/package.json

@@ -52,6 +52,16 @@
         "default": "./dist/cjs/sync.cjs"
       }
     },
+    "./stream": {
+      "import": {
+        "types": "./lib/stream.d.ts",
+        "default": "./lib/stream.js"
+      },
+      "require": {
+        "types": "./dist/cjs/stream.d.cts",
+        "default": "./dist/cjs/stream.cjs"
+      }
+    },
     "./browser/esm": {
       "types": "./dist/esm/index.d.ts",
       "default": "./dist/esm/index.js"
@@ -123,7 +133,7 @@
     "preversion": "npm run build && git add dist",
     "pretest": "npm run build",
     "test": "mocha 'test/**/*.{coffee,ts}'",
-    "test:legacy": "mocha --ignore test/api.web_stream.coffee --ignore test/api.stream.finished.coffee --ignore test/api.stream.iterator.coffee --loader=./test/loaders/legacy/all.js 'test/**/*.{coffee,ts}'"
+    "test:legacy": "mocha --ignore test/api.web_stream.coffee --ignore test/api.web_stream.ts --ignore test/api.stream.finished.coffee --ignore test/api.stream.iterator.coffee --loader=./test/loaders/legacy/all.js 'test/**/*.{coffee,ts}'"
   },
   "type": "module",
   "types": "dist/esm/index.d.ts",

packages/csv-parse/test/api.web_stream.ts

@@ -0,0 +1,45 @@
+import 'should'
+import {parse as parseStream} from '../lib/stream.js'
+import { CsvError } from '../lib/index.js'
+
+describe('API Web Stream', () => {
+
+  describe('stream/web/TransformStream', () => {
+
+    it('simple parse', async () => {
+      const stream = parseStream();
+      const writer = stream.writable.getWriter();
+      const reader = stream.readable.getReader();
+      await writer.write(Buffer.from("A,B,C\nD,E,F"));
+      await writer.close();
+      await reader.read().should.finally.eql({
+        done: false,
+        value: ['A', 'B', 'C'],
+      });
+      await reader.read().should.finally.eql({
+        done: false,
+        value: ['D', 'E', 'F'],
+      });
+      await reader.read().should.finally.eql({
+        done: true,
+        value: undefined,
+      });
+    })
+
+    it("cat error parse", async function () {
+      const stream = parseStream();
+      const writer = stream.writable.getWriter();
+      try {
+        await writer.write(Buffer.from("A,B,C\nD,E"));
+        await writer.close();
+        throw Error("Shall not be called");
+      } catch (err) {
+        if (!(err instanceof CsvError)) {
+          throw Error("Invalid error type");
+        }
+        err.code.should.eql("CSV_RECORD_INCONSISTENT_FIELDS_LENGTH");
+      }
+    });
+
+  })
+})