TypeScript OpenTimestamps (typescript-opentimestamps)

An OpenTimestamps client written in TypeScript

This project aims to provide a fully-tested, fully typed, OpenTimestamps Client. It currently supports stamping, upgrading, and verifying timestamps.

Table of Contents

1. Table of Contents
2. Background
3. Install
4. Usage
5. API
6. Contributing
7. License

Background

The OpenTimestamps project currently hosts a number of Server, Client, and CLI implementations. This is our contribution to that list, adding TypeScript to it.

The project may be used as-is in Typescript directly, or it may be compiled and packaged for usage in the browser or NodeJS modules.

Install

Installing the library is straightforward:

npm add @opentimestamps/typescript-opentimestamps

yarn add @opentimestamps/typescript-opentimestamps

pnpm add @opentimestamps/typescript-opentimestamps

The only run-time dependency is @noble/hashes.

Usage

Once installed the library can be directly imported:

import {
  type Timestamp,
  read as read,
  verify as verify,
  //
  verifiers,
} from '@opentimestamps/typescript-opentimestamps';

type VerificationResult = {
  attestations: Record<number, string[]>;
  errors: Record<string, Error[]>;
};

type AttestationEntry = [string, string[]];
type ErrorEntry = [string, Error[]];

const rawTimestamp: Uint8Array = Uint8Array.from(someTimestampBytes);
const timestamp: Timestamp = read(rawTimestamp);

verify(
  timestamp,
  verifiers,
).then(
  ({ attestations,  errors }: VerificationResult): void => {
    Object.entries(attestations).forEach(([time, verifiers]: AttestationEntry): void =>
      console.log(`Verifiers ${verifiers.join(', ')} attest to this timestamp as of ${time}`)
    );
    Object.entries(errors).forEach(([verifier, errorList]: ErrorEntry): void => {
      console.log(`${verifier} reported the following errors:`);
      errorList.forEach((error: Error): void => console.log(error.message));
    });
  },
);

API

This library exports the following types:

• Timestamp: a type alias containing version, file hash, and validation tree information.

It exports the following functions:

• info: obtain a human-readable description of the Timestamp's content.
• canShrink: determine whether the given Timestamp can be shrunk to a single attestation chain.
• canUpgrade: determine whether the given Timestamp ca be upgraded via a Calendar.
• canVerify: determine whether the given Timestamp can be verified in the blockchain(s).
• read: read a Uint8Array and transform it into a Timestamp if valid.
• shrink: eliminate all but the oldest attestation found in the given Timestamp for the given chain.
• submit: submit the given Timestamp to a Calendar for eventual inclusion in a blockchain.
• upgrade: upgrade the given Timestamp via a Calendar so as to make it independently verifiable.
• is: a TypeScript type predicate that simply applies validation to the given Timestamp.
• validate: validate the given parameter and determine whether it is indeed a Timestamp object.
• verify: verify the given Timestamp against the blockchain(s).
• verifiers: a set of predefined lambda functions that will query the blockchain via explorer-provider APIs to check for the presence of a given Merkle root on-chain.
• write: generate a Uint8Array consisting of the standard serialization of the given Timestamp value.

More in-depth information and prototypes can be found in the generated documentation.

Contributing

This project uses pnpm (think npm but faster), you'll need to install it if you haven't already.

You may clone the repository as usual:

git clone [email protected]:opentimestamps/typescript-opentimestamps.git
cd typescript-opentimestamps

Now, simply install all dependencies:

pnpm install

We provide several pnpm commands for your convenience:

• pnpm format: will run formatters and linters in all the codebase.
• pnpm build: will build all targets (TypeScript type declarations included) in the /dist directory.
• pnpm analyze: will analyze previous build.
• pnpm doc: will generate internal and external documentation in the /dist directory.
• pnpm clean: will remove the /dist directory entirely.
• pnpm test: will run all tests and report coverage on the whole codebase.
• pnpm reset: will run pnpm clean, and remove the /node_modules directory and pnpm-lock.yaml file, so as to completely reset the installation.

You'll probably want to run the tests first, build the documentation, and take it from there:

pnpm test
pnpm doc

Now navigate to /dist/docs/api/index.html (for the end-use documentation) or /dist/docs/internal/index.html (for developer documentation) and peruse the generated documentation at your leisure.

Please follow contribution guidelines at the GitHub repository, we encourage PRs!

License

GNU Lesser General Public License v3 or later, see LICENSE.