Get ISO Date without the Milliseconds using JavaScript

Get ISO Date without the Milliseconds using JavaScript #

To get an ISO date without the milliseconds:

1. Split the ISO string on the dot . character.
2. Access the array element at index 0.
3. Append the letter Z to the end of the result.
4. For example, date.toISOString().split('.')[0] + 'Z'.

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// ✅ If you have a Date object
const date = new Date();
const withoutMs = date.toISOString().split('.')[0] + 'Z';
console.log(withoutMs); // 👉️ "2022-01-19T07:32:40Z"

// ✅ If you have a plain ISO string
const isoStr = '2022-07-21T09:35:31.820Z';
const withoutMilliseconds = isoStr.split('.')[0] + 'Z';
console.log(withoutMilliseconds); // 👉️ "2022-07-21T09:35:31Z"

The split method splits a string on the provided separator and returns an array of substrings.

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const isoStr = '2022-07-21T09:35:31.820Z';

// 👇️ ['2022-07-21T09:35:31', '820Z']
console.log(isoStr.split('.'));

ISO formatted dates look like: YYYY-MM-DDTHH:mm:ss.sssZ, so we can split the string on the dot ., which separates the seconds from the milliseconds.

The last step is to access the array element at index 0 and append the Z character.

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const isoStr = '2022-07-21T09:35:31Z';

const withoutMilliseconds = isoStr.includes('.')
  ? isoStr.split('.')[0] + 'Z'
  : isoStr;

// 👇️ "2022-07-21T09:35:31Z"
console.log(withoutMilliseconds);

We used the String.includes method to check if the ISO string contains a dot . character.

The ternary operator is very similar to in if/else statement.

In other words, if the ISO string contains a dot, we split the string and remove the milliseconds part, otherwise return the string as is.

You only have to do this if your ISO string might not contain the milliseconds part, e.g. because you already removed it, or it was never there to begin with.