@thi.ng/transducers/partition-when.js

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

import { __iter, iterator } from "./iterator.js";
import { isReduced } from "./reduced.js";
function partitionWhen(...args) {
  return __iter(partitionWhen, args, iterator) || (([init, complete, reduce]) => {
    const pred = args[0];
    const f = args[1] === true ? pred() : pred;
    let chunk;
    return [
      init,
      (acc) => {
        if (chunk?.length) {
          acc = reduce(acc, chunk);
          chunk = null;
        }
        return complete(acc);
      },
      (acc, x) => {
        if (f(x)) {
          chunk && (acc = reduce(acc, chunk));
          chunk = isReduced(acc) ? null : [x];
        } else {
          chunk ? chunk.push(x) : chunk = [x];
        }
        return acc;
      }
    ];
  });
}
export {
  partitionWhen
};