In JavaScript, we use the filter method to filter items stored in an array using a callback. We use the map method to create a new array using the old array using the logic passed inside a callback.

Use popular 'grammar of data' syntax to filter and subset your two-dimensional JavaScript arrays and more. Here's how to use Arquero for data wrangling in Observable JavaScript and Node.js.

Functional programming with arrays Although JavaScript’s arrays are very capable out of the box, the functional paradigm improves the clarity and maintainability of array code.