iter-tools-es/impls/$bisect/async-bisect.js

The iterable toolbox

const {
  asyncIterableCurry
} = require('../../internal/async-iterable.js');

const {
  AsyncBisector
} = require('../../internal/async-bisector.js');

const {
  __asyncToArray
} = require('../$to-array/async-to-array.js');

const {
  __asyncPeekerate
} = require('../$peekerate/async-peekerate.js');

async function* asyncIndexStrategy(split, {
  at
}, source) {
  const _source = at < 0 ? await __asyncToArray(source) : source;

  const idx = at < 0 ? _source.length + at : at;
  const peekr = await __asyncPeekerate(_source);

  try {
    while (!peekr.done) {
      if (peekr.index === idx) yield split;
      yield peekr.value;
      await peekr.advance();
    }
  } finally {
    peekr.return();
  }
}

exports.asyncIndexStrategy = asyncIndexStrategy;

async function* asyncConditionStrategy(split, {
  at: predicate
}, source) {
  let i = 0;
  let splat = false;

  for await (const value of source) {
    if (!splat && (await predicate(value, i++))) {
      yield split;
      splat = true;
    }

    yield value;
  }
}

exports.asyncConditionStrategy = asyncConditionStrategy;

function __asyncBisect(source, at) {
  const strategy = typeof at === 'number' ? asyncIndexStrategy : asyncConditionStrategy;
  return new AsyncBisector(source, strategy, {
    at
  });
}

exports.__asyncBisect = __asyncBisect;
const asyncBisect = /*#__PURE__*/asyncIterableCurry(__asyncBisect, {
  forceSync: true
});
exports.asyncBisect = asyncBisect;