How to Convert a String to a Date in JavaScript

Converting strings to dates in JavaScript is a common task, especially when dealing with web forms, API responses, or any scenario where you need to manipulate dates stored in string format. JavaScript's Date object and various libraries make this task straightforward, allowing you to focus on more complex logic in your applications.

The article below explores strategies in converting a string to a date.

What is the Date object in JavaScript?

The Date object in JavaScript is the key to converting string representations of dates into date objects. Here's the simplest form of conversion using the Date constructor:

const dateString = "2024-02-15"; // ISO format
const dateObject = new Date(dateString);
console.log(dateObject);

This example assumes the date string is in the ISO 8601 format (YYYY-MM-DD). The Date constructor parses the string and creates a Date object representing the specified date and time in the local time zone.

Parsing non-standard date strings

For date strings not in ISO 8601 format, the parsing might not be as straightforward, and results can vary across browsers. In such cases, it's advisable to use a consistent format or a library like date-fns or moment.js for parsing.

However, for simple conversions, you can manually parse the components of the date string and use the Date constructor that accepts year, month, and day as parameters:

const dateString = "15/02/2024"; // DD/MM/YYYY format
const parts = dateString.split("/");

// Note: months are 0-based
const year = parseInt(parts[2], 10);
const month = parseInt(parts[1], 10) - 1;
const day = parseInt(parts[0], 10);

const dateObject = new Date(year, month, day);
console.log(dateObject);

Using libraries for complex parsing

When dealing with various date formats or needing more complex date manipulations, using a library can save time and ensure consistency. date-fns and moment.js are two popular choices that provide straightforward methods for converting strings to dates.

Example with date-fns

import { parseISO } from 'date-fns';

const dateString = "2024-02-15";
const dateObject = parseISO(dateString);
console.log(dateObject);

Example with moment.js

import moment from 'moment';

const dateString = "15-02-2024";
const dateObject = moment(dateString, "DD-MM-YYYY").toDate();
console.log(dateObject);

Using these libraries not only simplifies parsing non-standard formats but also provides robust functions for formatting, comparing, and manipulating dates.

Converting string representations to date objects is essential for any web application dealing with dates. By understanding the Date object and leveraging external libraries when necessary, developers can handle a wide range of date formats, ensuring their applications can process dates accurately and efficiently.