Lodash tricks I use

2025-02-24

Comparison to JavaScript ES6

For most of my career, I've stuck with Javascript ES6 Array.prototype patterns for manipulating collections. These are for the most part, good enough.

However, there are some benefits to using Lodash; it performs much better with very high amounts of records, and its syntax can be more idiomatic.

Turn a record into an array

I prefer to use Lodash with the _.chain function so that the syntax is similar to JS ES6 collection methods that I'm used to.

// ES6
Object.values(data);

// Lodash
_.chain(data).values().value();

Debugging Lodash

The Lodash tap method calls a function on the collection, without affecting it. It is extremely useful for debugging, because you can move the _.tap(console.log) to any point in your Lodash chain to inspect it.

// ES6
data.forEach((x) => {
  console.log(x);
  return x;
});

// Lodash
_.chain(data).tap(console.log).value();

Sorting

One reason to use Lodash is that ES6's sort() mutates the original array, while Lodash's sortBy and orderBy return a new sorted array.

Sorting by date

The use of JavaScript's Date object is the fastest way to blood on the floor.

There are several problems with it; such as performance when working with large datasets, no timezone, and the fact that Dates are mutable (so any arithmetic performed on them permanently changes them).

For this reason, when sorting dates, I'm always sorting a string. Because sort works on alphanumeric values, sorting by date is usually as easy as sorting the strings.

Sort by date

// ES6
date.sort((a, b) => b.date.localeCompare(a.date));
// Lodash
_.chain(data).orderBy("date").value();

Sort by optional date

// ES6
data.sort((a, b) => {
  const dateA = a.date || "";
  const dateB = b.date || "";
  return dateB.localeCompare(dateA);
});
// Lodash
_.chain(data)
  .sortBy((x) => x.date || "")
  .reverse()
  .value();

Filter out expired dates

// Lodash
_.chain(data).filter((x) => !x.date || x.date > new Date().toISOString());