Abstract

persists JSON objects to a file . Keeps several files and loads older files if the latest is broken

Contents

• Meta
• Class Persist
  • Parameters
  • Methods
    • readData
    • saveObjectToFile

Meta

| | | | --- | --- | | File | persist.js | | Abstract | persists JSON objects to a file . Keeps several files and loads older files if the latest is broken | | Author | Volker Böhm | | Copyright | Copyright ( c ) 2020 Volker Böhm | | License | This software is licensed under the GNU LESSER GENERAL PUBLIC LICENSE Version 3 . It is furnished "as is" , without any support , and with no warranty , express or implied , as to its usefulness for any purpose . |

Class Persist

new Persist(configuration)

Creates a new persistance support class

Example

const persist = new Persist( { keepFiles: 5 })
persist.saveObjectToFile('.', 'helloworld.json', { message: 'hello world' } )
const dataRead = persist.readData('.', 'helloworld.json')
// prints 'hello world'
console.log(dataRead.message)

Persist Parameters

| Name | Type | Description | | ---------- | ------------ | ----------------- | | configuration | Object | configuration options | |

configuration properties

| Name | Type | Description | | ---------- | ------------ | ----------------- | | keepFiles | number | amount of file versions to keep ( including the recently written file ) | |

Persist Methods

readData

readData (directory, filenameBasis) => {Object}

Reads data from a file

readData Parameters

| Name | Type | Description | | ---------- | ------------ | ----------------- | | directory | string | directory to delete file | | | filenameBasis | string | basis filename of the file . The | |

readData returns

| Type | Description | | ---- | ----------- | | Object | the object read . |

saveObjectToFile

async saveObjectToFile (directory, filenameBasis, objectToSave) => {undefined}

Stringifies a JSON and writes it to a file . It will automatically add a timestamp to the provided "base" filename It does not throws errors , but logs write errors to the console

saveObjectToFile Parameters

| Name | Type | Description | | ---------- | ------------ | ----------------- | | directory | string | directory to delete file | | | filenameBasis | string | basis filename of the file . The | | | objectToSave | Object | object to save as JSON | |

saveObjectToFile returns

| Type | Description | | ---- | ----------- | | undefined | |