Refactor to unpack `options` into private properties

This change makes these properties consistent with other classes in this library. This change is also the simplest way to let the TypeScript language server understand that these properties are not null.

diff --git a/src/core.js b/src/core.js
index 428879037f67c7fb8cacaaa64a27a53161d04ca5..333db9a3568b0e522000346dffa284b16acd1109 100644 (file)
--- a/src/core.js
+++ b/src/core.js
@@ -221,11 +221,17 @@ export class CSVReader extends ReadableStream {
  */
 export class CSVTransformer extends TransformStream {
   #fn;
-  #options;
   #concurrent = [];
   #batch = [];
   #firstChunk = true;
 
+  #handleHeaders;
+  #rawInput;
+  #rawOutput;
+  #onError;
+  #maxBatchSize;
+  #maxConcurrent;
+
   /**
    * @param {TransformationFunction} fn A function to process a row or rows of CSV data.
    * 
@@ -253,42 +259,39 @@ export class CSVTransformer extends TransformStream {
       flush: (controller) => this.#flush(controller),
     });
 
-    options.handleHeaders ??= false;
-    options.rawInput ??= false;
-    options.rawOutput ??= false;
-    options.onError ??= null;
-    options.maxBatchSize ??= 1;
-    options.maxConcurrent ??= 1;
+    this.#handleHeaders = options.handleHeaders ?? false;
+    this.#rawInput = options.rawInput ?? false;
+    this.#rawOutput = options.rawOutput ?? false;
+    this.#onError = options.onError ?? null;
+    this.#maxBatchSize = options.maxBatchSize ?? 1;
+    this.#maxConcurrent = options.maxConcurrent ?? 1;
 
     this.#fn = fn;
-    this.#options = options;
   }
 
   async #wrappedHeaderFn(row) {
-    const { onError, handleHeaders } = this.#options;
-    if (typeof handleHeaders === 'boolean') {
-      return handleHeaders ? await this.#wrappedFn(row) : row;
+    if (typeof this.#handleHeaders === 'boolean') {
+      return this.#handleHeaders ? await this.#wrappedFn(row) : row;
     }
-    if (Array.isArray(handleHeaders)) {
-      return handleHeaders;
+    if (Array.isArray(this.#handleHeaders)) {
+      return this.#handleHeaders;
     }
-    if (onError === null) { return await handleHeaders(row); }
-    try { return await handleHeaders(row); }
-    catch (e) { return await onError(row, e, handleHeaders); }
+    if (this.#onError === null) { return await this.#handleHeaders(row); }
+    try { return await this.#handleHeaders(row); }
+    catch (e) { return await this.#onError(row, e, this.#handleHeaders); }
   }
 
   async #wrappedFn(row) {
-    const { onError } = this.#options;
-    if (onError === null) { return await this.#fn(row); }
+    if (this.#onError === null) { return await this.#fn(row); }
     try { return await this.#fn(row); }
-    catch (e) { return await onError(row, e, this.#fn); }
+    catch (e) { return await this.#onError(row, e, this.#fn); }
   }
 
   #enqueueRow(row, controller) {
     if (row === null || row === undefined) { // Input row is consumed without emitting any output row
       return;
     }
-    else if (this.#options.rawOutput || typeof row === 'string') {
+    else if (this.#rawOutput || typeof row === 'string') {
       controller.enqueue(row);
     }
     else if (Array.isArray(row) && Array.isArray(row[0])) { // Multiple rows returned, enqueue each row separately
@@ -319,8 +322,7 @@ export class CSVTransformer extends TransformStream {
   }
 
   async #transform(chunk, controller) {
-    const { rawInput, maxBatchSize, maxConcurrent } = this.#options;
-    const row = rawInput ? chunk : JSON.parse(chunk);
+    const row = this.#rawInput ? chunk : JSON.parse(chunk);
 
     if (this.#firstChunk) {
       this.#firstChunk = false;
@@ -329,9 +331,9 @@ export class CSVTransformer extends TransformStream {
       return;
     }
 
-    if (maxBatchSize > 1) {
+    if (this.#maxBatchSize > 1) {
       this.#batch.push(row);
-      if (this.#batch.length === maxBatchSize) {
+      if (this.#batch.length === this.#maxBatchSize) {
         this.#concurrent.push(this.#wrappedFn(this.#batch));
         this.#batch.length = 0;
       }
@@ -340,7 +342,7 @@ export class CSVTransformer extends TransformStream {
       this.#concurrent.push(this.#wrappedFn(row));
     }
 
-    if (this.#concurrent.length === maxConcurrent) {
+    if (this.#concurrent.length === this.#maxConcurrent) {
       await this.#enqueueConcurrent(controller);
     }
   }