lis-db

lis-db

LIS (Local Interface for Storage), is a "key-value" frontend database build on indexedDB and with typescript support^[1].

API

The library offers three functions (write, read and erase)

write

write( key:string, value:any ): Promise<void>^[2] Can save persistent data with "key-value" structure, similar to localStorage API.

import { write } from 'lis-db'

write( 'hello', 'Hello World!' ).then( () => {
  console.log( 'Data Saved' )
} )

read

read<T>( ...keys:string[] ): Promise<T[]>^[2] is used to read data from the database. It takes as many keys as you want and its promise is resolved with an array of the saved values. You can set the array elements type with the generic type T^[3]

import { read } from 'lis-db'

read<string>( 'hello' ).then( values:string[] => {
  const [ hello ] = values  // Using Desestucturing (recommended)
  console.log( hello ) // 'Hello World!'
} )

Also you can use as operator with a tupla to get values with a different type

import { read, write } from 'lis-db'

write( 'num', 7 ).then( () => {
  // Waiting for save data to read it
  read( 'num', 'hello' ).then( values => {
    type tupla = [ number, string ]
    const [ num, hello ] = values as tupla
    console.log( typeof num, typeof hello )  // 'number', 'string'
  } )
} )

Warning: Undeclared values will be null

import { read } from 'lis-db'

// "x" was not written
read( 'x' ).then( values => {
  const [ x ] = values
  console.log( x )  // null
} )

erase

erase( key:string ): Promise<void>^[2] is used to erase data from the database

import { erase, read } from 'lis-db'

read<string>( 'hello' ).then( values => {
  const [ hello ] = values
  console.log( hello )  // 'Hello World!'
  erase( 'hello' ).then( () => {
    // Waiting for erase data to read it
    read<string>( 'hello' ).then( values => {
      const [ hello ] = values
      console.log( hello )  // null
    } )
  } )
} )

• If do you use this library with javascript, types features will be incompatible.
• This async function will resolve its promise when finish its task.
• If you don't use it, the promise will be resolved with unknown[] type