feat: get byte from buffer by index.

Author: ghosind

src/dynamicBuffer.ts

@@ -87,6 +87,9 @@ export class DynamicBuffer {
    */
   private used: number;
 
+  // eslint-disable-next-line no-undef
+  [index: number]: number | undefined;
+
   /**
    * Create a DynamicBuffer with default settings.
    *
@@ -187,6 +190,20 @@ export class DynamicBuffer {
     if (data) {
       this.append(data);
     }
+
+    // eslint-disable-next-line no-constructor-return
+    return new Proxy(this, {
+      get: (target: this, p: string | symbol, receiver: any) => {
+        if (Reflect.has(target, p)) {
+          return Reflect.get(target, p, receiver);
+        }
+        if (Number(p) >= 0) {
+          return Reflect.apply(Reflect.get(target, 'read', receiver), target, [Number(p)]);
+        }
+
+        return Reflect.get(target, p, receiver);
+      },
+    });
   }
 
   /**

test/read.spec.ts

@@ -3,6 +3,35 @@ import { describe, it } from 'mocha';
 
 import { DynamicBuffer } from '../src';
 
+describe('Get by index tests', () => {
+  it('Test getting by index with legal ranges', () => {
+    const buffer = new DynamicBuffer();
+    const str = 'Hello world';
+
+    buffer.append(str);
+
+    for (let i = 0; i < str.length; i += 1) {
+      assert.equal(buffer[i], str.charCodeAt(i));
+    }
+  });
+
+  it('Test getting by index with a negative offset', () => {
+    const buffer = new DynamicBuffer();
+
+    buffer.append('Hello world');
+
+    assert.equal(buffer[-1], undefined);
+  });
+
+  it('Test getting by index with a offset larger than buffer length', () => {
+    const buffer = new DynamicBuffer();
+
+    buffer.append('Hello world');
+
+    assert.equal(buffer[buffer.length + 1], undefined);
+  });
+});
+
 describe('Read tests', () => {
   it('Test read without parameter', () => {
     const buffer = new DynamicBuffer();