dead-easy-json

JSON is easy

“Dead-easy JSON serialization for JavaScript. Bidirectional object synchronization with async support„

Showcase

v2 should be the latest drastic change. v2 is not compatible with v1

Quickstart

const myFile = require(`dead-easy-json`)(`./myJson.json`).file;
// // myFile = {} This is implied. You can override this behavior
// myFile.a.b = 3; // ERROR; because a is undefined
myFile.a = {};  // Ok; written to file system SYNCHRONOUSLY by default
myFile.a.b = 3; // Ok; written to file system SYNCHRONOUSLY by default
/*
The json file will look like this
{
 a: {
  b: 3
 }
}
*/
console.log(myFile.a.b); // 3
console.log(myFile.a.c); // undefined
// console.log(myFile.d.e); // ERROR

A more controlled example

const JSONrequire = require(`dead-easy-json`);
const handler = JSONrequire(`${__dirname}/myJson.json`, 
  {} //The default object. Can be set to {"ur property":{"values":[]}} or [1,{2:3}] for example.
  , {
  writeInterval: 100, // When this value is set, the object tracks changes and writes those changes at once every interval. Don't worry, it doesn't write when there are no changes. Read # writeInterval section for more

  // Options for JSON.stringify
  replacer: null,
  space: 2,

  // Writes the JSON to the variable asynchronously
  // You must call handler.close() to exit properly
  watch: true
});
const { file: myFile } = handler;

handler.watchCallback = () => console.log("detected file change")

myFile.a = [1,2,3];

console.log(myFile.a); // undefined
// This obviously should be inside an async function
await handler.writeAwait; //  type: ignore
console.log(myFile.a); // [1, 2, 3]

// You can also immediately write the file
handler.write();

// and asynchronously write the file as well
await handler.writeAsync();

// Taking a sub-property object is also supported
myFile[1] = {}
const myObj = myFile[1]
myObj.b = 2 // Written in disk

handler.close(); // MUST if watch: true

How writeInterval works

The changes are queued for the next writeInterval ms and then the callback is called. This change listener does not check whether the properties are actually the same e.g) setting a.b = 3 and then setting it to a.b = 3. Even though they are two same values, the file will still be written

Specifications

All the properties of the main file proxy is a proxy itself as well

const { file } = require(`dead-easy-json`)(`data.json`);
file.property = {} // Written in disk
const prop = file.property;
prop.a = 42 // Also written in disk

// This is a no brainer but rewriting the property itself doesn't work
let prop = file.property;
prop = 3 // This just sets prop to a new reference

When saving the json file, all references are PRESERVED

const prop = file.property
setTimeout(() => {
  console.log(prop.a) // prints 42; reference is PRESERVED
}, 10000)
// Save the file to be
/*
{
  "property": { "a": 42 }
}
*/

When saving the json file, type {} should be matched with type {} and [] with []

file.property = {}
// Save the file to be
/*
{
  "property": []
}
*/
// ^ ERROR because the reference preservation system forbids this
// Also I do NOT see any reason for anyone to use [] and {} interchangably

// Doing
file.property = [] 
// In the code however, is allowed

Some gatchas

• Default objs can be nested, but they are written in sync regardless of writeInterval.

• Even if there is a writeInterval the variable is immediately accessible. Its just written in memory before disk

• The reader will rewrite the file when initially loaded if it is a blank file ex) "". If it is a blank, the file be defaultObj or {} apon constructing the proxy. This is done SYNCHRONOUSLY

• Setting the .file to a new object will invoke another proxy. This will ALWAYS rewrite the file synchronously (note: this was an elaborate design choice ) (must be like myObj.file = {} not file = {} <- this will not invoke the new proxy)

• Watch writes to the json variable. This will not reset the write timer

• Because the reference is preserved, myArray[3] for example will point to the [3] when the file changes. If you do not want this behavior, do something like const val = myArray[3] then only use val.

• Object assignments will give you a proxy on nested objects. This might be confusing

const handler = require(`dead-easy-json`)(`./file.json`, {});
const file = handler.file;

let obj = {
 prop:[],
};
file.test = obj;
// obj.prop = [1,2]; // doesn't work
obj.prop.push(42); // works

obj = file.test;
obj.prop = 42; // works
obj.someattr = `hi`; // works

Donations

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