ms
Use this package to easily convert various time formats to milliseconds.
## Examples
```ts
ms('2 days') // 172800000
ms('1d') // 86400000
ms('10h') // 36000000
ms('2.5 hrs') // 9000000
ms('2h') // 7200000
ms('1m') // 60000
ms('5s') // 5000
ms('1y') // 31557600000
ms('100') // 100
ms('-3 days') // -259200000
ms('-1h') // -3600000
ms('-200') // -200
```
### Convert from Milliseconds
```ts
ms(60000) // "1m"
ms(2 * 60000) // "2m"
ms(-3 * 60000) // "-3m"
ms(ms('10 hours')) // "10h"
```
### Time Format Written-Out
```ts
ms(60000, { long: true }) // "1 minute"
ms(2 * 60000, { long: true }) // "2 minutes"
ms(-3 * 60000, { long: true }) // "-3 minutes"
ms(ms('10 hours'), { long: true }) // "10 hours"
```
### Input Formats (Units)
```ts
type Years = 'years' | 'year' | 'yrs' | 'yr' | 'y'
type Months = 'months' | 'month' | 'mo'
type Weeks = 'weeks' | 'week' | 'w'
type Days = 'days' | 'day' | 'd'
type Hours = 'hours' | 'hour' | 'hrs' | 'hr' | 'h'
type Minutes = 'minutes' | 'minute' | 'mins' | 'min' | 'm'
type Seconds = 'seconds' | 'second' | 'secs' | 'sec' | 's'
type Milliseconds = 'milliseconds' | 'millisecond' | 'msecs' | 'msec' | 'ms'
type Unit = Years | Months | Weeks | Days | Hours | Minutes | Seconds | Milliseconds
```
These formats can be lowercase (`minutes`), uppercase (`MINUTES`), or capitalized (`Minutes`). There can be a space (`2 minutes`) or not (`2minutes`).
> [!NOTE]
> The casing and spacing is enforced at a type level if you use [`parseStrict`](#enhanced-type-safety).
If no unit is passed (`2`), the unit will default to `Milliseconds`. Fractional input values like `0.5m`, `-0.5m`, `.5m`, and `-.5m` are supported.
## Installation
You can install this package using a package manager like [npm](https://docs.npmjs.com/cli/v11/commands/npm-install), [yarn](https://yarnpkg.com/cli/add), [pnpm](https://pnpm.io/cli/add), [deno](https://docs.deno.com/runtime/reference/cli/add), or [bun](https://bun.com/docs/cli/add).
```bash
npm install ms
yarn add ms
pnpm add ms
deno add npm:ms
bun add ms
```
## Features
- Works in both browsers and server runtimes like [Node.js](https://nodejs.org), [Deno](https://deno.com), or [Bun](https://bun.sh)
- If a number is supplied to `ms`, a string with a unit is returned
- If a string that contains the number is supplied, it returns it as a number (e.g.: it returns `100` for `'100'`)
- If you pass a string with a number and a valid unit, the number of equivalent milliseconds is returned
## TypeScript support
As of `v3.0`, this package includes TypeScript definitions.
For added safety, we're using [Template Literal Types](https://www.typescriptlang.org/docs/handbook/2/template-literal-types.html) (added in [TypeScript 4.1](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-1.html)). This ensures that you don't accidentally pass `ms` values that it can't process.
This won't require you to do anything special in most situations, but you can also import the `StringValue` type from `ms` if you need to use it.
```ts
import { ms, type StringValue } from 'ms';
// Using the exported type.
function example(value: StringValue) {
ms(value);
}
// This function will only accept a string compatible with `ms`.
example('1 h');
```
In this example, we use a [Type Assertion](https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#type-assertions) to coerce a `string`.
```ts
import { ms, type StringValue } from 'ms';
// Type assertion with the exported type.
function example(value: string) {
try {
// A string could be "wider" than the values accepted by `ms`, so we assert
// that our `value` is a `StringValue`.
//
// It's important to note that this can be dangerous (see below).
ms(value as StringValue);
} catch (error: Error) {
// Handle any errors from invalid values.
console.error(error);
}
}
// This function will accept any string, which may result in a bug.
example('any value');
```
You may also create a custom Template Literal Type.
```ts
import { ms } from 'ms';
type OnlyDaysAndWeeks = `${number} ${'days' | 'weeks'}`;
// Using a custom Template Literal Type.
function example(value: OnlyDaysAndWeeks) {
// The type of `value` is narrower than the values `ms` accepts, which is
// safe to use without coercion.
ms(value);
}
// This function will accept "# days" or "# weeks" only.
example('5.2 days');
```
## Advanced Usage
### Helper Functions
As of `v3.0`, you can import `parse` and `format` separately.
```ts
import { parse, format } from 'ms';
parse('1h'); // 3600000
format(2000); // "2s"
```
### Enhanced Type Safety
If you want strict type checking for the input value, you can use `parseStrict`.
```ts
import { parseStrict } from 'ms';
parseStrict('1h'); // 3600000
function example(s: string) {
return parseStrict(str); // tsc error
}
```
## Edge Runtime Support
`ms` is compatible with the [Edge Runtime](https://edge-runtime.vercel.app/). It can be used inside environments like [Vercel Edge Functions](https://vercel.com/edge) as follows:
```ts
// Next.js (pages/api/edge.js) (npm i next@canary)
// Other frameworks (api/edge.js) (npm i -g vercel@canary)
import { ms } from 'ms';
const start = Date.now();
export default (req) => {
return new Response(`Alive since ${ms(Date.now() - start)}`);
};
export const config = {
runtime: 'experimental-edge',
};
```
## Related Packages
- [ms.macro](https://github.com/knpwrs/ms.macro) - Run `ms` as a macro at build-time.
## Caught a Bug?
1. [Fork](https://help.github.com/articles/fork-a-repo/) this repository to your own GitHub account and then [clone](https://help.github.com/articles/cloning-a-repository/) it to your local device
2. Link the package to the global module directory: `npm link`
3. Within the module you want to test your local development instance of ms, just link it to the dependencies: `npm link ms`. Instead of the default one from npm, Node.js will now use your clone of ms!
As always, you can run the tests using: `npm test`
[^1]: Internet Explorer is not supported