@thi.ng/transducers-stats/deque.js

Transducers for statistical / technical analysis

class Deque {
  constructor(samples, pred) {
    this.samples = samples;
    this.pred = pred;
  }
  index = [];
  head() {
    return this.samples[this.index[0]];
  }
  add(x) {
    const { index, samples, pred } = this;
    while (index.length && pred(samples[index[index.length - 1]], x)) {
      index.pop();
    }
    index.push(samples.length - 1);
  }
  shift() {
    const { index } = this;
    if (index[0] === 0) index.shift();
    for (let i = 0; i < index.length; i++) index[i]--;
  }
}
export {
  Deque
};