Completed Array implementation; CoffeelessProgrammer#2 IP

Author: CoffeelessProgrammer

Data-Structures/Arrays/My_Array_Implementation.ts

@@ -0,0 +1,127 @@
+// RUN:   deno run Data-Structures/Arrays/My_Array_Implementation.ts
+
+type NumIndexedObject = { [index: number]: any };
+
+class MyArray<T> {
+
+  public length: number;
+  private data: NumIndexedObject;
+
+  constructor() {
+    this.length = 0;
+    this.data = Object.create({});
+  }
+
+  public get(index: number): T | null {
+    if(index > 0 && index < this.length) {
+      return this.data[index];
+    }
+
+    return null;
+  }
+
+  public push(item: T): number {
+    this.data[this.length] = item;  // Add item to end of array
+    ++this.length;                  // Add 1 to array length
+
+    return this.length;
+  }
+
+  public pop(): T | null {
+    if(this.length > 0) {
+      const lastItem = this.data[this.length-1];  // Retrieve last item
+      delete this.data[this.length-1];            // Delete last item
+      --this.length;                              // Decrement array length by 1
+
+      return lastItem;
+    }
+
+    return null;
+  }
+
+  public deleteIndex(index: number): T | null {
+    if(index > 0 && index < this.length) {
+
+      const requestedItem = this.data[index];
+      this.shiftItemsLeftAfterIndex(index);
+
+      return requestedItem;
+    }
+
+    return null;
+  }
+
+  public insertItemAtIndex(index: number, item: T): number | null {
+    if(index > 0 && index < this.length) {
+      this.shiftItemsRightAtIndex(index);
+      this.data[index] = item;
+      return this.length;
+    }
+
+    return null;
+  }
+
+  private shiftItemsLeftAfterIndex(index: number): void {
+    for (let i=index; i < this.length-1; ++i) {
+      this.data[i] = this.data[i+1];
+    }
+
+    --this.length;
+    delete this.data[this.length];
+  }
+
+  private shiftItemsRightAtIndex(index: number): void {
+    ++this.length;
+
+    for (let i=this.length-1; i > index; --i) {
+      this.data[i] = this.data[i-1];
+    }
+
+    delete this.data[index];
+  }
+}
+
+
+let helloArray = new MyArray<string>();
+
+helloArray.push('Hello');   // O(1)
+helloArray.push('world');
+console.log(helloArray);
+
+helloArray.pop();           // O(1)
+console.log(helloArray);
+
+helloArray.push('Deno');
+helloArray.push('!');
+console.log(helloArray);
+
+console.log('At index 2:', helloArray.get(2));
+
+// -------------------------------------------
+
+let sokka = new MyArray<string>();
+
+sokka.push('s');
+sokka.push('o');
+sokka.push('c');
+sokka.push('k');
+sokka.push('a');
+console.log(sokka);
+
+console.log('Element deleted:', sokka.deleteIndex(2));  // O(n)
+console.log(sokka);
+
+sokka.insertItemAtIndex(2, 'k');  // O(n)
+console.log(sokka);
+
+
+
+// --------------------------- Terminal Output: ---------------------------
+// MyArray { length: 2, data: { 0: "Hello", 1: "world" } }
+// MyArray { length: 1, data: { 0: "Hello" } }
+// MyArray { length: 3, data: { 0: "Hello", 1: "Deno", 2: "!" } }
+// At index 2: !
+// MyArray { length: 5, data: { 0: "s", 1: "o", 2: "c", 3: "k", 4: "a" } }
+// Element deleted: c
+// MyArray { length: 4, data: { 0: "s", 1: "o", 2: "k", 3: "a" } }
+// MyArray { length: 5, data: { 0: "s", 1: "o", 2: "k", 3: "k", 4: "a" } }