Merge c0b3fb6 into db6c0b4

yenhsuan · Jan 3, 2019 · 33ab2b4 · 33ab2b4
2 parents db6c0b4 + c0b3fb6
commit 33ab2b4
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diff --git a/src/data_structures/stack.js b/src/data_structures/stack.js
@@ -28,6 +28,10 @@ class Stack {
   peek() {
     return this.isEmpty() ? null : internal(this).array[this.size() - 1];
   }
+
+  toString() {
+    return this.isEmpty() ? '' : internal(this).array.toString();
+  }
 }
 
 module.exports = Stack;
diff --git a/test/data_structures/stack.test.js b/test/data_structures/stack.test.js
@@ -65,4 +65,20 @@ describe('# Stack', () => {
       should(stack.pop()).be.Null();
     });
   });
+
+  describe('toString', () => {
+    it('should return empty string if stack is empty', () => {
+      const stack = new Stack();
+      stack.toString().should.be.equal('');
+    });
+
+    it('should return the same format as Array.toString()', () => {
+      const array = ['Javascript', 'Data', 'Structure'];
+      const stack = new Stack();
+      array.forEach((elem) => {
+        stack.push(elem);
+      });
+      stack.toString().should.be.equal(array.toString());
+    });
+  });
 });