Features

Installation

npm install immutable superstruct struma --save

yarn add immutable superstruct struma

Usage

1. Define a Schema

import{number,object,string}from'superstruct';constUserSchema=object({name:string(),age:number(),preferences:object({theme:string(),}),});

2. Initialize Struma

import{Struma}from'struma';import{JSONFile}from'struma/adapters/node';constadapter=newJSONFile('db.json');constdb=newStruma(UserSchema,adapter);

3. Update and Save State

import{Map}from'immutable';// Update stateconstnewState=Map({name:'Alice',age:30,preferences:Map({theme:'dark',}),});// Either you can use plain js object too, it will// auto resolves using `fromJS` method from `immutable`db.state=newState;// Save state to write into db.jsonawaitdb.write();

// db.json{"name":"Alice","age":30,"preferences":{"theme":"dark"}}

4. Read State

console.log((awaitdb.state).toJS());// { name: 'Alice', age: 30, preferences: { theme: 'dark'}}

5. Access Snapshot History

console.log((awaitdb.snapshots).toJS());// Array of historical states

API

new Struma(schema, adapter)

db.state

db.write()

db.snapshots

Custom Adapters

importtype{AdapterasAsyncAdapter,SyncAdapter}from'lowdb';exportinterfaceAdapter<T>{read:()=>ReturnType<AsyncAdapter<T>['read']|SyncAdapter<T>['read']>;write:(data:T)=>ReturnType<AsyncAdapter<T>['write']|SyncAdapter<T>['write']>;}

Tip

For common case, you can go tolowdbDocumentation

Examples

Node.js / ES Modules

import{Struma}from'struma';import{JSONFile}from'struma/adapters/node';import{number,object,string}from'superstruct';constUserSchema=object({name:string(),age:number(),});constadapter=newJSONFile('db.json');constdb=newStruma(UserSchema,adapter);(async()=>{// Update statedb.state={name:'Alice',age:25};// Save stateawaitdb.write();// Read stateconsole.log((awaitdb.state).toJS());// { name: 'Alice', age: 25 }// Access snapshot historyconsole.log((awaitdb.snapshots).toJS());// [null, { name: 'Alice', age: 25 }]})();

UMD

<scriptsrc="https://unpkg.com/immutable"></script><scriptsrc="https://unpkg.com/superstruct"></script><scriptsrc="https://unpkg.com/struma"></script><script>// Define a schemaconstUserSchema=Superstruct.object({name:Superstruct.string(),age:Superstruct.string(),});constadapter=newStruma.adapters.LocalStorage('db');constdb=newStruma(UserSchema,adapter);(async()=>{// Update stateconstnewState={name:'John',age:'30'};db.state=newState;// Save state to write into LocalStorageawaitdb.write();// Read stateconststate=awaitdb.state;console.log('Current State:',state.toJS());// { name: 'John', age: '30' }// Access snapshot historyconstsnapshots=awaitdb.snapshots;console.log('Snapshot History:',snapshots.toJS());// [null, { name: 'John', age: '30' }]})();</script>

Support