What

Brief

This is a standalone Deque data structure from the data-structure-typed collection. If you wish to access more data structures or advanced features, you can transition to directly installing the complete data-structure-typed package

How

install

npm

npm i deque-typed --save

yarn

yarn add deque-typed

snippet

basic Deque creation and push/pop operations

 // Create a simple Deque with initial values
    const deque = new Deque([1, 2, 3, 4, 5]);

    // Verify the deque maintains insertion order
    console.log([...deque]); // [1, 2, 3, 4, 5];

    // Check length
    console.log(deque.length); // 5;

    // Push to the end
    deque.push(6);
    console.log(deque.length); // 6;

    // Pop from the end
    const last = deque.pop();
    console.log(last); // 6;

Deque shift and unshift operations

 const deque = new Deque<number>([20, 30, 40]);

    // Unshift adds to the front
    deque.unshift(10);
    console.log([...deque]); // [10, 20, 30, 40];

    // Shift removes from the front (O(1) complexity!)
    const first = deque.shift();
    console.log(first); // 10;

    // Verify remaining elements
    console.log([...deque]); // [20, 30, 40];
    console.log(deque.length); // 3;

Deque peek at both ends

 const deque = new Deque<number>([10, 20, 30, 40, 50]);

    // Get first element without removing
    const first = deque.at(0);
    console.log(first); // 10;

    // Get last element without removing
    const last = deque.at(deque.length - 1);
    console.log(last); // 50;

    // Length unchanged
    console.log(deque.length); // 5;

Deque for...of iteration and reverse

 const deque = new Deque<string>(['A', 'B', 'C', 'D']);

    // Iterate forward
    const forward: string[] = [];
    for (const item of deque) {
      forward.push(item);
    }
    console.log(forward); // ['A', 'B', 'C', 'D'];

    // Reverse the deque
    deque.reverse();
    const backward: string[] = [];
    for (const item of deque) {
      backward.push(item);
    }
    console.log(backward); // ['D', 'C', 'B', 'A'];

Deque as sliding window for stream processing

 interface DataPoint {
      timestamp: number;
      value: number;
      sensor: string;
    }

    // Create a deque-based sliding window for real-time data aggregation
    const windowSize = 3;
    const dataWindow = new Deque<DataPoint>();

    // Simulate incoming sensor data stream
    const incomingData: DataPoint[] = [
      { timestamp: 1000, value: 25.5, sensor: 'temp-01' },
      { timestamp: 1100, value: 26.2, sensor: 'temp-01' },
      { timestamp: 1200, value: 25.8, sensor: 'temp-01' },
      { timestamp: 1300, value: 27.1, sensor: 'temp-01' },
      { timestamp: 1400, value: 26.9, sensor: 'temp-01' }
    ];

    const windowResults: Array<{ avgValue: number; windowSize: number }> = [];

    for (const dataPoint of incomingData) {
      // Add new data to the end
      dataWindow.push(dataPoint);

      // Remove oldest data when window exceeds size (O(1) from front)
      if (dataWindow.length > windowSize) {
        dataWindow.shift();
      }

      // Calculate average of current window
      let sum = 0;
      for (const point of dataWindow) {
        sum += point.value;
      }
      const avg = sum / dataWindow.length;

      windowResults.push({
        avgValue: Math.round(avg * 10) / 10,
        windowSize: dataWindow.length
      });
    }

    // Verify sliding window behavior
    console.log(windowResults.length); // 5;
    console.log(windowResults[0].windowSize); // 1; // First window has 1 element
    console.log(windowResults[2].windowSize); // 3; // Windows are at max size from 3rd onwards
    console.log(windowResults[4].windowSize); // 3; // Last window still has 3 elements
    console.log(dataWindow.length); // 3;

API docs & Examples

API Docs

Live Examples

Examples Repository

Data Structures

Standard library data structure comparison

Benchmark

Built-in classic algorithms

Software Engineering Design Standards