@thi.ng/transducers/iterator.js

Collection of ~170 lightweight, composable transducers, reducers, generators, iterators for functional data transformations

import { NO_OP, SEMAPHORE } from "@thi.ng/api/api";
import { isIterable } from "@thi.ng/checks/is-iterable";
import { ensureTransducer } from "./ensure.js";
import { push } from "./push.js";
import { isReduced, unreduced } from "./reduced.js";
function* iterator(xform, src) {
  const rfn = ensureTransducer(xform)(push());
  const complete = rfn[1];
  const reduce = rfn[2];
  for (let x of src) {
    const y = reduce([], x);
    if (isReduced(y)) {
      yield* unreduced(complete(y.deref()));
      return;
    }
    if (y.length) {
      yield* y;
    }
  }
  yield* unreduced(complete([]));
}
function* iterator1(xform, src) {
  const reduce = ensureTransducer(xform)([NO_OP, NO_OP, (_, x) => x])[2];
  for (let x of src) {
    let y = reduce(SEMAPHORE, x);
    if (isReduced(y)) {
      y = unreduced(y.deref());
      if (y !== SEMAPHORE) {
        yield y;
      }
      return;
    }
    if (y !== SEMAPHORE) {
      yield y;
    }
  }
}
const __iter = (xform, args, impl = iterator1) => {
  const n = args.length - 1;
  return isIterable(args[n]) ? args.length > 1 ? impl(xform.apply(null, args.slice(0, n)), args[n]) : impl(xform(), args[0]) : void 0;
};
export {
  __iter,
  iterator,
  iterator1
};