iter-tools-es/impls/$forkerate/forkerate.js

The iterable toolbox

const {
  ensureIterable
} = require('../../internal/iterable.js');

const {
  Exchange
} = require('../../internal/fork.js');

const {
  Peekerator
} = require('../../internal/peekerator.js');

const _ = Symbol.for('_');

class Forkerator extends Peekerator {
  static from(source) {
    const exchange = new Exchange(ensureIterable(source)[Symbol.iterator]());
    return super.from(exchange.fork(), exchange);
  }

  constructor(iterator, first, exchange) {
    super(iterator, first);
    this[_].exchange = exchange;
  }

  advance(n = 1) {
    for (let i = 0; i < n; i++) {
      super.advance();

      this[_].exchange.advance();
    }

    return this;
  }

  fork() {
    return this[_].exchange.fork();
  }

  [Symbol.iterator]() {
    return this[_].exchange.fork();
  }

}

function __forkerate(source) {
  return Forkerator.from(source);
}

exports.__forkerate = __forkerate;

function wrapWithEnsureIterable(fn) {
  return source => fn(ensureIterable(source));
}

const forkerate = wrapWithEnsureIterable(__forkerate);
exports.forkerate = forkerate;