Queue

hojas · hojas · commit 0370d4e45ad1 · 2024-01-14T19:25:50.000+08:00
diff --git a/src/data-structures/queue/Queue.test.ts b/src/data-structures/queue/Queue.test.ts
@@ -0,0 +1,76 @@
+import { describe, expect, it } from 'vitest'
+import { Queue } from './Queue'
+
+describe('queue', () => {
+  it('should create empty queue', () => {
+    const queue = new Queue()
+
+    expect(queue).toBeDefined()
+    expect(queue.toString()).toBe('')
+  })
+
+  it('should enqueue data to queue', () => {
+    const queue = new Queue()
+
+    queue.enqueue(1)
+    queue.enqueue(2)
+
+    expect(queue.toString()).toBe('1,2')
+  })
+
+  it('should peek data from queue', () => {
+    const queue = new Queue()
+
+    expect(queue.peek()).toBeUndefined()
+
+    queue.enqueue(1)
+    queue.enqueue(2)
+
+    expect(queue.peek()).toBe(1)
+    expect(queue.peek()).toBe(1)
+  })
+
+  it('should check queue size', () => {
+    const queue = new Queue()
+
+    expect(queue.size()).toBe(0)
+
+    queue.enqueue(1)
+    queue.enqueue(2)
+
+    expect(queue.size()).toBe(2)
+  })
+
+  it('should check if queue is empty', () => {
+    const queue = new Queue()
+
+    expect(queue.isEmpty()).toBe(true)
+
+    queue.enqueue(1)
+
+    expect(queue.isEmpty()).toBe(false)
+  })
+
+  it('should dequeue data from queue', () => {
+    const queue = new Queue()
+
+    queue.enqueue(1)
+    queue.enqueue(2)
+
+    expect(queue.dequeue()).toBe(1)
+    expect(queue.dequeue()).toBe(2)
+    expect(queue.dequeue()).toBeUndefined()
+    expect(queue.isEmpty()).toBe(true)
+  })
+
+  it('should be possible to enqueue/dequeue objects', () => {
+    const queue = new Queue<{ value: string }>()
+
+    queue.enqueue({ value: 'test1' })
+    queue.enqueue({ value: 'test2' })
+
+    expect(queue.size()).toBe(2)
+    expect(queue.dequeue()?.value).toBe('test1')
+    expect(queue.dequeue()?.value).toBe('test2')
+  })
+})
diff --git a/src/data-structures/queue/Queue.ts b/src/data-structures/queue/Queue.ts
@@ -0,0 +1,29 @@
+export class Queue<T> {
+  private queue: T[] = []
+
+  public enqueue(value: T) {
+    this.queue.push(value)
+  }
+
+  public dequeue() {
+    return this.queue.shift()
+  }
+
+  public peek() {
+    return this.queue[0]
+  }
+
+  public size() {
+    return this.queue.length
+  }
+
+  public isEmpty() {
+    return this.queue.length === 0
+  }
+
+  toString(callback?: (item: T) => string) {
+    if (callback)
+      return this.queue.map(callback).toString()
+    return this.queue.toString()
+  }
+}
diff --git a/src/data-structures/stack/Stack.test.ts b/src/data-structures/stack/Stack.test.ts
@@ -70,14 +70,14 @@ describe('stack', () => {
   })
 
   it('should be possible to push/pop objects', () => {
-    const stack = new Stack()
+    const stack = new Stack<{ value: string, key: string }>()
 
     stack.push({ value: 'test1', key: 'key1' })
     stack.push({ value: 'test2', key: 'key2' })
 
     const stringifier = (value: any) => `${value.key}:${value.value}`
     expect(stack.toString(stringifier)).toBe('key2:test2,key1:test1')
-    expect(stack.pop().value).toBe('test2')
-    expect(stack.pop().value).toBe('test1')
+    expect(stack.pop()?.value).toBe('test2')
+    expect(stack.pop()?.value).toBe('test1')
   })
 })
diff --git a/src/data-structures/stack/Stack.ts b/src/data-structures/stack/Stack.ts
@@ -1,7 +1,7 @@
-export class Stack {
-  private items: any[] = []
+export class Stack<T> {
+  private items: T[] = []
 
-  push(item: any) {
+  push(item: T) {
     this.items.push(item)
   }
 
@@ -25,7 +25,7 @@ export class Stack {
     this.items = []
   }
 
-  toString(callback?: (item: any) => string) {
+  toString(callback?: (item: T) => string) {
     const list = this.items.toReversed()
     if (callback)
       return list.map(callback).toString()
