Lodash filter with limit

Question

Is there a way to filter the first n elements from an array that match a criteria?

I know you can filter and then call take but doesn't that go through the whole list instead of exiting after reaching the limit?

_(books).filter(function(book) {return book.pages > 10}).take(5).value();

Answer 1

If the iterator function passed to the _.forEach() function returns false, the iteration is stopped immediately.

The following filter function illustrates how _.forEach() can be used to solve your use case.

function filter(books, maxCount) {
  var results = [];
  _.forEach(books, function(book) {
    if (results.length === maxCount) {
      return false;
    }
    if (book.pages > 10) {
      results.push(book);
    }
  });
  return results;
}


var N = 5;
var books = new Array(20);

// Give each book a page count equal to its books index.
_.forEach(books, function(v, i) {books[i] = {pages: i}});

console.log(filter(books, N));

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