das das in javascript

To create a data structure called a das (short for data and stack), you can use an array in JavaScript. There are several ways to implement a das, but one approach is to use an array and a pointer to keep track of the top of the stack. Here is an example implementation:

index.tsx
class Das {
  constructor() {
    this.data = [];
    this.top = -1;
  }

  push(item) {
    this.data[++this.top] = item;
  }

  pop() {
    if (this.isEmpty()) {
      return null;
    }
    const item = this.data[this.top];
    delete this.data[this.top--];
    return item;
  }

  peek() {
    if (this.isEmpty()) {
      return null;
    }
    return this.data[this.top];
  }

  isEmpty() {
    return this.top === -1;
  }

  size() {
    return this.top + 1;
  }
}
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In this example, the push method adds an item to the top of the stack by first incrementing the top pointer and then assigning the item to that position in the array. The pop method removes the item from the top of the stack by first checking if the das is empty, then retrieving the item from the top of the stack, deleting that position in the array, and finally decrementing the top pointer. The peek method returns the item at the top of the stack without removing it. The isEmpty and size methods provide information about the current state of the das.