Go's time.Sub in TypeScript

How to use

Install via yarn add locutus and import: import { Sub } from 'locutus/golang/time/Sub'.

Or with CommonJS: const { Sub } = require('locutus/golang/time/Sub')

Use a bundler that supports tree-shaking so you only ship the functions you actually use. Vite, webpack, Rollup, and Parcel all handle this. For server-side use this is less of a concern.

Examples

These examples are extracted from test cases that automatically verify our functions against their native counterparts.

#	code	expected result
1	Sub('2026-03-03T13:14:15.500Z', '2026-03-03T13:14:15.000Z')	500
2	Sub('2026-03-03T13:14:10.000Z', '2026-03-03T13:14:15.000Z')	-5000

Notes

• Returns the duration in milliseconds between two instants (left - right).

Here's what our current TypeScript equivalent to Go's time.Sub looks like.

TSTypeScript JSJavaScript TSStandalone TS JSStandalone JS

Copy code

type GoTimeInput = Date | string | number

const toTimeDate = (value: GoTimeInput): Date => {
  const date = value instanceof Date ? new Date(value.getTime()) : new Date(value)
  if (Number.isNaN(date.getTime())) {
    throw new TypeError('Sub(): invalid date input')
  }
  return date
}

export function Sub(left: GoTimeInput, right: GoTimeInput): number {
  //      discuss at: https://locutus.io/golang/time/Sub
  // parity verified: Go 1.23
  //     original by: Kevin van Zonneveld (https://kvz.io)
  //          note 1: Returns the duration in milliseconds between two instants (left - right).
  //       example 1: Sub('2026-03-03T13:14:15.500Z', '2026-03-03T13:14:15.000Z')
  //       returns 1: 500
  //       example 2: Sub('2026-03-03T13:14:10.000Z', '2026-03-03T13:14:15.000Z')
  //       returns 2: -5000

  return toTimeDate(left).getTime() - toTimeDate(right).getTime()
}

const toTimeDate = (value) => {
  const date = value instanceof Date ? new Date(value.getTime()) : new Date(value)
  if (Number.isNaN(date.getTime())) {
    throw new TypeError('Sub(): invalid date input')
  }
  return date
}

export function Sub(left, right) {
  //      discuss at: https://locutus.io/golang/time/Sub
  // parity verified: Go 1.23
  //     original by: Kevin van Zonneveld (https://kvz.io)
  //          note 1: Returns the duration in milliseconds between two instants (left - right).
  //       example 1: Sub('2026-03-03T13:14:15.500Z', '2026-03-03T13:14:15.000Z')
  //       returns 1: 500
  //       example 2: Sub('2026-03-03T13:14:10.000Z', '2026-03-03T13:14:15.000Z')
  //       returns 2: -5000

  return toTimeDate(left).getTime() - toTimeDate(right).getTime()
}

Improve this function

Locutus is a community effort following The McDonald's Theory: we ship first iterations, hoping others will improve them. If you see something that could be better, we'd love your contribution.

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We have 47 Go functions so far - help us add more

Got a rainy Sunday afternoon and a taste for a porting puzzle?

• Get inspiration from Go strings documentation, Go strings source, Go strings examples source, GopherJS.
• Click "New file" in the appropriate folder on GitHub. This will fork the project to your account, directly add the file to it, and send a Pull Request to us.

We will then review it. If it's useful to the project and in line with our contributing guidelines your work will become part of Locutus and you'll be automatically credited in the authors section accordingly.

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