Improve documentation.

README.md

@@ -26,6 +26,52 @@ Use `DEBUG=p-transform:*` environment variable.
 
 For custom debug name set `logName` option at PTransform constructor or `transform` argument.
 
+<a name="PTransform"></a>
+
+## PTransform
+
+**Kind**: global class
+
+- [PTransform](#PTransform)
+  - [new PTransform([options])](#new_PTransform_new)
+  - [.flushQueue()](#PTransform+flushQueue) ⇒
+  - [.queuedTransform(chunk, encoding)](#PTransform+queuedTransform) ⇒
+
+<a name="new_PTransform_new"></a>
+
+### new PTransform([options])
+
+PTransform
+
+| Param                  | Type                  | Description                            |
+| ---------------------- | --------------------- | -------------------------------------- |
+| [options]              | <code>Object</code>   | Options object forwarded to Transform. |
+| [options.logName]      | <code>String</code>   | Custom name for logger.                |
+| [options.transform]    | <code>function</code> | Transform function.                    |
+| [options.queueOptions] | <code>Object</code>   | Options forwarded to PQueue instance.  |
+
+<a name="PTransform+flushQueue"></a>
+
+### pTransform.flushQueue() ⇒
+
+Wait for queue idle.
+
+**Kind**: instance method of [<code>PTransform</code>](#PTransform)
+**Returns**: Promise<void>
+<a name="PTransform+queuedTransform"></a>
+
+### pTransform.queuedTransform(chunk, encoding) ⇒
+
+Queued transform operation.
+
+**Kind**: instance method of [<code>PTransform</code>](#PTransform)
+**Returns**: Promise
+
+| Param    | Type                |
+| -------- | ------------------- |
+| chunk    | <code>Object</code> |
+| encoding | <code>String</code> |
+
 ## License
 
 Apache-2.0

index.js

@@ -6,6 +6,14 @@ const { pipeline: _pipeline, Transform } = require('stream');
 const pipeline = promisify(_pipeline);
 
 class PTransform extends Transform {
+  /**
+   * PTransform
+   *
+   * @param {Object} [options] - Options object forwarded to Transform.
+   * @param {String} [options.logName] - Custom name for logger.
+   * @param {Function} [options.transform] - Transform function.
+   * @param {Object} [options.queueOptions] - Options forwarded to PQueue instance.
+   */
   constructor(options = {}) {
     // transform is used locally, forward undefined to prevent conflicts.
     super({ objectMode: true, ...options });
@@ -33,19 +41,23 @@ class PTransform extends Transform {
 
   /**
    * Wait for queue idle.
-   * @return Promise
+   *
+   * @return Promise<void>
    */
   flushQueue() {
     return this.queue.onIdle();
   }
 
   /**
    * Queued transform operation.
+   *
+   * @param {Object} chunk
+   * @param {String} encoding
    * @return Promise
    */
-  async queuedTransform(chunk, enc) {
+  async queuedTransform(chunk, encoding) {
     try {
-      const maybeChunk = await this._transform(chunk, enc);
+      const maybeChunk = await this._transform(chunk, encoding);
       if (maybeChunk) {
         this.push(maybeChunk);
       }
@@ -61,9 +73,9 @@ class PTransform extends Transform {
     setTimeout(() => callback());
   }
 
-  _flush(cb) {
+  _flush(callback) {
     this.debug('_flush');
-    this.flushQueue().then(() => cb());
+    this.flushQueue().then(() => callback());
   }
 }