feat: add toJSON method.

Author: ghosind

README.md

@@ -79,3 +79,5 @@ yarn add dynamic-buffer
   - `encoding`: The character encoding for output string.
   - `start`: The start byte offset.
   - `end`: The end byte offset.
+
+- `toJSON()`: Exports data to a JSON representation.

src/dynamicBuffer.ts

@@ -196,6 +196,36 @@ export class DynamicBuffer {
     return this.buffer.toString(encoding || this.encoding, startOffset, endOffset);
   }
 
+  /**
+   * Returns a JSON representation of this buffer.
+   *
+   * ```js
+   * const buf = new DynamicBuffer();
+   * buf.append("Hello");
+   * console.log(JSON.stringify(buf));
+   * // {"type":"Buffer","data":[72,101,108,108,111]}
+   * ```
+   */
+  toJSON() {
+    const data: number[] = [];
+
+    if (this.buffer && this.used > 0) {
+      // eslint-disable-next-line no-restricted-syntax
+      for (const pair of this.buffer.entries()) {
+        if (pair[0] >= this.used) {
+          break;
+        }
+
+        data.push(pair[1]);
+      }
+    }
+
+    return {
+      type: 'Buffer',
+      data,
+    };
+  }
+
   /**
    * Ensures the buffer size is at least equal to the expect size.
    *

test/dynamicBuffer.spec.ts

@@ -213,6 +213,29 @@ describe('Export string tests', () => {
   });
 });
 
+describe('Exports to JSON object', () => {
+  it('Test toJSON() without writes data', () => {
+    const buffer = new DynamicBuffer();
+
+    const buf = buffer.toJSON();
+
+    assert.equal(buf.type, 'Buffer');
+    assert.deepEqual(buf.data, []);
+    assert.equal(JSON.stringify(buf), '{"type":"Buffer","data":[]}');
+  });
+
+  it('Test toJSON() with data', () => {
+    const buffer = new DynamicBuffer();
+
+    buffer.append('Hello');
+    const buf = buffer.toJSON();
+
+    assert.equal(buf.type, 'Buffer');
+    assert.deepEqual(buf.data, [72, 101, 108, 108, 111]);
+    assert.equal(JSON.stringify(buf), '{"type":"Buffer","data":[72,101,108,108,111]}');
+  });
+});
+
 describe('Resize tests', () => {
   it('Test resize()', () => {
     const buffer = new DynamicBuffer();