feat: ✨ add support for custom methods

src/index.ts

@@ -1,28 +1,39 @@
 import * as varint from 'varint';
 
-export default class BufWrapper {
+export default class BufWrapper<
+  Plugins extends BufWrapperPlugins = BufWrapperPlugins
+> {
   /**
    * The wrapped NodeJS buffer
    */
   public buffer: Buffer;
+  /**
+   * Current offset (used for reading)
+   */
+  public offset: number;
+  /**
+   * Options that apply to the current `BufWrapper` instance
+   * */
+  public options?: BufWrapperOptions<Plugins>;
+  /**
+   * Installed plugins so you can access them from this object
+   */
+  public plugins?: Plugins;
 
-  /** Current offset */
-  private offset: number;
   /** List of buffers, used for the `oneConcat` option */
   private buffers: Buffer[];
-  /** Options that apply to the current `BufWrapper` instance */
-  private options?: BufWrapperOptions;
 
   /**
    * Create a new buffer wrapper instance
    * @param buffer The NodeJS buffer to wrap, optional
    * @param options Options to apply to the buffer wrapper, optional
    */
-  public constructor(buffer?: Buffer, options?: BufWrapperOptions) {
+  public constructor(buffer?: Buffer, options?: BufWrapperOptions<Plugins>) {
     this.buffer = buffer || Buffer.alloc(0);
     this.offset = 0;
     this.buffers = [];
     this.options = options;
+    this.plugins = options?.plugins;
   }
 
   /**
@@ -432,13 +443,19 @@ export default class BufWrapper {
    * array.
    * @param value The buffers to write (array of buffers)
    */
-  private writeToBuffer(...buffers: Buffer[]): void {
+  public writeToBuffer(...buffers: Buffer[]): void {
     if (this.options?.oneConcat === true) this.buffers.push(...buffers);
     else this.buffer = Buffer.concat([this.buffer, ...buffers]);
   }
 }
 
-interface BufWrapperOptions {
+type BufWrapperPlugins = {
+  [key: string]: {
+    [key: string]: (buf: BufWrapper, ...args: any[]) => any;
+  };
+};
+
+interface BufWrapperOptions<Plugins> {
   /**
    * Whether or not to run the `Buffer#concat` method when writing.
    * When set to `true`, you will have to call the `BufWrapper#finish`
@@ -449,4 +466,9 @@ interface BufWrapperOptions {
    * to the buffer.
    */
   oneConcat?: boolean;
+  /**
+   * Plugins you want to install on the BufferWrapper intance
+   * you are about to create
+   */
+  plugins?: Plugins;
 }

test/plugins.test.js

@@ -0,0 +1,52 @@
+const BufWrapper = require('../dist').default;
+const { assert } = require('chai');
+
+const CStringPlugin = {
+  /**
+   * @param {BufWrapper} buf
+   * @param {String} string
+   */
+  writeCString(buf, string) {
+    const buffer = Buffer.alloc(Buffer.byteLength(string) + 1);
+    buffer.write(string);
+    buf.writeToBuffer(buffer);
+  },
+
+  /**
+   * @param {BufWrapper} buf
+   */
+  readCString(buf) {
+    let cursor = buf.offset;
+    let length = 0;
+    while (buf.buffer[cursor] !== 0x00) {
+      length++;
+      cursor++;
+    }
+    const bytes = buf.buffer.slice(buf.offset, length);
+    buf.offset += length + 1;
+    return bytes.toString();
+  },
+};
+
+describe('Plugins', () => {
+  it('CString Write', () => {
+    const buf = new BufWrapper(null, {
+      plugins: { CStringPlugin },
+    });
+
+    buf.plugins.CStringPlugin.writeCString(buf, 'Hello World!');
+
+    assert.equal(buf.buffer.toString('hex'), '48656c6c6f20576f726c642100');
+  });
+
+  it('CString Read', () => {
+    const buf = new BufWrapper(
+      Buffer.from('48656c6c6f20576f726c642100', 'hex'),
+      {
+        plugins: { CStringPlugin },
+      }
+    );
+
+    assert.equal(buf.plugins.CStringPlugin.readCString(buf), 'Hello World!');
+  });
+});