mingo/esm/operators/accumulator/lastN.js

MongoDB query language for in-memory objects

import { computeValue } from "../../core/_internal";
import { isInteger } from "../../util";
import { errExpectNumber, INT_OPTS } from "../expression/_internal";
import { $push } from "./push";
const $lastN = (collection, expr, options) => {
  const copts = options;
  const m = collection.length;
  const n = computeValue(copts?.local?.groupId, expr.n, null, copts);
  const foe = options.failOnError;
  if (!isInteger(n) || n < 1) {
    return errExpectNumber(foe, "$lastN 'n'", INT_OPTS.pos);
  }
  return $push(
    m <= n ? collection : collection.slice(m - n),
    expr.input,
    options
  );
};
export {
  $lastN
};