@divanov/infinite-react-carousel/src/carousel/array.js

Infinite carousel for react

class CircularArray {
  array = [];

  key = [];

  origin = null;

  get length() {
    return this.array.length;
  }

  constructor(n, origin = null) {
    this.array = [];
    if (typeof n === 'number') {
      this.array = new Array(n);
    } else if (typeof n === 'object' && Array.isArray(n)) {
      this.array = n;
    } else if (typeof n === 'object' && n.length > 0 && n instanceof NodeList) {
      for (let i = 0; i < n.length; i += 1) {
        this.array.push(n[i]);
      }
      this.key = this.array.map((item) => {
        const {
          dataset: {
            carouselkey
          }
        } = item;
        return carouselkey;
      });
    } else {
      throw new Error('can not create array');
    }
    this.origin = origin;
  }

  toString = (array) => {
    const result = [];
    const newArray = array || this.array;
    for (let i = 0; i < newArray.length; i += 1) {
      const item = newArray[i];
      if (typeof item === 'object' && item instanceof Array) result.push(`[${this.toString(item)}]`);
      else if (typeof item === 'object') result.push(JSON.stringify(item));
      else result.push(item.toString());
    }
    return result.join(',');
  };

  get = (i) => {
    let result;
    if (i < 0 || i < this.length - this.array.length) {
      result = this.array[
        -i % this.array.length === 0
          ? 0
          : this.array.length + (i % this.array.length)
      ];
    } else {
      result = this.array[i % this.array.length];
    }
    return result;
  };

  getKeyIndex = (i) => {
    const originItem = this.origin.get(i);
    const { dataset: { carouselkey } } = originItem;
    return this.key.indexOf(carouselkey);
  }

  getIndex = (i) => {
    let result;
    if (i < 0 || i < this.length - this.array.length) {
      result = -i % this.array.length === 0
        ? 0
        : this.array.length + (i % this.array.length);
    } else {
      result = i % this.array.length;
    }
    return result;
  }

  set = (i, v) => {
    if (i < 0 || i < this.length - this.array.length) {
      throw new Error('can not set index < 0');
    }
    if (i >= this.length) {
      const newArr = new Array(i - this.length + 1);
      this.array = this.array.concat(newArr);
      this.array.splice(i, 1, v);
    } else {
      this.array[this.getIndex(i)] = v;
    }
  };
}

export default CircularArray;