https://github.com/pedromsilvapt/data-transactional-log

Safely and reliable serialize and write data to a file in transactions, and read them back again
https://github.com/pedromsilvapt/data-transactional-log

Last synced: 11 days ago
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Safely and reliable serialize and write data to a file in transactions, and read them back again

• Host: GitHub
• URL: https://github.com/pedromsilvapt/data-transactional-log
• Owner: pedromsilvapt
• Created: 2019-03-08T22:13:14.000Z (almost 6 years ago)
• Default Branch: master
• Last Pushed: 2019-03-09T12:06:35.000Z (almost 6 years ago)
• Last Synced: 2024-12-17T19:24:01.627Z (22 days ago)
• Language: TypeScript
• Size: 8.79 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Transactional Log

> Safely and reliable serialize and write data to a file in transactions, and read them back again

# Installation

```shell

npm install --save data-transactional-log

```

# Usage

```typescript

import { TransactionalLog } from 'data-transactional-log';

const log = new TransactionalLog( 'actions.log' );

// Each log is composed of transactions. Each transaction is simply a list of values of the same time.

await log.writeTransaction( [ 1, 2, 3 ] );

// In many cases we might want to create transactions with only one item. For that we can use the shortcut method

await log.write( 1 );

// The methods above are fine when we have the transaction's items upfront, but sometimes we do not. For that we can explicitly create a transaction

const transaction = log.transaction();

try {

    await transaction.write( 1 );

    

    await transaction.writeMany( [ 2, 3 ] );

    await transaction.commit();

} catch {

    // It is usually good practices to wrap the transaction inside a try/catch to prevent transaction-leaks:

    // those can happen when a transaction is never commited neither aborted

    await transaction.abort();

}

// After having written to a log, we can retrieve those transactions

for await ( let transaction of transaction.readTransactions() ) {

    console.log( transaction.blocks, transaction.commitId );

    // Would print the following

    // [ 1, 2, 3 ] 1

    // [ 1 ] 2

    // [ 1, 2, 3 ] 3

0}

// Sometimes we might not necessarily care about the transactions themselves, and just need the actual data

for await ( let block of transaction.read() ) {

    console.log( block ); 

    // Would print the numbers, one in each line

    // 1 2 3 1 1 2 3

}

// For convenience, we might need the last transaction read. For that we have

console.log( transaction.lastTransactionRead );

console.log( transaction.lastTransactionIdRead );

```