circularr/node/index.js

Circular fixed size array

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = void 0;

var _defineProperty2 = _interopRequireDefault(require("@babel/runtime/helpers/defineProperty"));

let _Symbol$iterator;

_Symbol$iterator = Symbol.iterator;

class Circularr {
  static from(source) {
    const arr = new Circularr(source.length);

    for (let i = 0; i < source.length; i++) {
      arr._data[i] = source[i];
    }

    return arr;
  }

  constructor(length) {
    (0, _defineProperty2.default)(this, "_data", void 0);
    (0, _defineProperty2.default)(this, "_index", void 0);
    this._data = new Array(length);
    this._index = 0;
  }

  *[_Symbol$iterator]() {
    for (let i = 0; i < this._data.length; i++) {
      yield this._data[(i + this._index) % this._data.length];
    }
  }

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

  fill(value) {
    for (let i = 0; i < this._data.length; i++) {
      this._data[i] = value;
    }

    this._index = 0;
    return this;
  }

  clear() {
    this._data = new Array(this._data.length);
    this._index = 0;
    return this;
  }

  shift(value) {
    const returnValue = this._data[this._index];
    this._data[this._index] = value;
    this._index = (this._index + 1) % this._data.length;
    return returnValue;
  }

  unshift(value) {
    this._index = (this._index + this._data.length - 1) % this._data.length;
    const returnValue = this._data[this._index];
    this._data[this._index] = value;
    return returnValue;
  }

  slice(startIndex, endIndex) {
    return Circularr.from(Array.from(this).slice(startIndex, endIndex));
  }

  trim() {
    const data = Array.from(this);
    let startIndex = 0;
    let endIndex = data.length;

    for (let i = 0; i < data.length; i++) {
      if (typeof data[i] !== 'undefined') {
        break;
      }

      startIndex++;
    }

    for (let i = data.length - 1; i >= 0; --i) {
      if (typeof data[i] !== 'undefined') {
        break;
      }

      endIndex--;
    }

    return Circularr.from(data.slice(startIndex, endIndex));
  }

  at(index) {
    if (index < 0 || index >= this._data.length) {
      return;
    }

    return this._data[(index + this._index) % this._data.length];
  }

  wrapAt(index) {
    return this._data[(index + this._index) % this._data.length];
  }

}

exports.default = Circularr;