String Is ISO Formatted Date

Introduction

In this lab, we will explore how to determine if a given string is a valid date string in the simplified extended ISO format (ISO 8601). We will use the Date constructor and its associated methods to create a Date object from the string and check its validity. By the end of the lab, you will have a better understanding of how to work with dates in JavaScript and how to validate them using the ISO format.

Skills Graph

Checking if a String is in ISO Format

To check if a given string is in the simplified extended ISO format (ISO 8601), follow these steps:

1. Open the Terminal/SSH and type node to start practicing coding.
2. Use the Date constructor to create a Date object from the given string.
3. Check if the produced date object is valid using Date.prototype.valueOf() and Number.isNaN().
4. Compare the ISO formatted string representation of the date with the original string using Date.prototype.toISOString().
5. If the strings match and the date is valid, return true. Otherwise, return false.

Here is an example code snippet:

const isISOString = (val) => {
  const d = new Date(val);
  return !Number.isNaN(d.valueOf()) && d.toISOString() === val;
};

isISOString("2020-10-12T10:10:10.000Z"); // true
isISOString("2020-10-12"); // false

This function will return true if the string is in ISO format, and false otherwise.

Summary

Congratulations! You have completed the String Is ISO Formatted Date lab. You can practice more labs in LabEx to improve your skills.