livecodingspace-app/public/lib/gundb/lib/promise.js

/* Promise Library v1.1 for GUN DB
*  Turn any part of a gun chain into a promise, that you can then use
*  .then().catch() pattern.
*  In normal gun doing var item = gun.get('someKey'), gun returns a reference
*  to the someKey synchroneously. Using a reference is quite helpful in making
*  graph structures, so I have chosen to follow the following paradigm.
*  Whenever a promise is resolved, gun will return an object of data, I will
*  wrap that data in an object together with the reference like so:
*  {ref: gunRef, data: data}.
* This code is freely given in the spirit of open source MIT license.
* Author: Jachen Duschletta / 2019
*/

/*
* Function promOnce
* @param limit - due to promises resolving too fast if we do not set a timer
*  we will not be able receive any data back from gun before returning the promise
*  works both following a Chain.get and a Chain.map (limit only applies to map)
*  If no limit is chosen, defaults to 100 ms (quite sufficient to fetch about 2000 nodes or more)
* @param opt - option object
* @return {ref: gunReference, data: object / string (data), key: string (soulOfData)}
*/

Gun.chain.promOnce = async function (limit, opt) {
 var gun = this, cat = gun._;
 if(!limit){limit = 100}
 if(cat.subs){
  var array = [];
  gun.map().once((data, key)=>{
    var gun = this;
    array.push(new Promise((res, rej)=>{
      res({ref: gun, data:data, key:key});
    })
   )
 }, opt);
  await sleep(limit);
  return Promise.all(array)
} else {
  return (new Promise((res, rej)=>{
    gun.once(function (data, key) {
      var gun = this;
      res({ref:gun,data:data,key:key});
      }, opt);
    }))
  }
 var chain = gun.chain();
 return chain;
}

function sleep (limit) {
 return (new Promise((res, rej)=>{
   setTimeout(res, limit);
 }))
}

/*
* Function promPut
* @param item (string / object) - item to be put to that key in the chain
* @param opt - option object
* @return object - Returns an object with the ref to that node that was just
*  created as well as the 'ack' which acknowledges the put was succesful
*  object {ref: gunReference, ack: acknowledgmentObject}
* If put had an error we can catch the return via .catch
*/

Gun.chain.promPut = async function (item, opt) {
  var gun = this;
  return (new Promise((res, rej)=>{
    gun.put(item, function(ack) {
        if(ack.err){console.log(ack.err); ack.ok=-1; res({ref:gun, ack:ack})}
        res({ref:gun, ack:ack});
    }, opt);
  }))
}

/*
* Function promSet
* @param item (string / object) - item to be set into a list at this key
* @param opt - option object
* @return object - Returns object with the ref to that node that was just
*  created as well as the 'ack' which acknowledges the set was succesful
*  object {ref: gunReference, ack: acknowledgmentObject}
* If set had an error we can catch the return via .catch
*/

Gun.chain.promSet = async function(item, opt){
	var gun = this, soul;
  var cb = cb || function(){};
	opt = opt || {}; opt.item = opt.item || item;
  return (new Promise(async function (res,rej) {
    if(soul = Gun.node.soul(item)){ item = Gun.obj.put({}, soul, Gun.val.link.ify(soul)) }
		if(!Gun.is(item)){
			if(Gun.obj.is(item)){;
				item = await gun.back(-1).get(soul = soul || Gun.node.soul(item) || gun.back('opt.uuid')()).promPut(item);
        item = item.ref;
			}
			res(gun.get(soul || (Gun.state.lex() + Gun.text.random(7))).promPut(item));
		}
		item.get(function(soul, o, msg){
      var ack = {};
			if(!soul){ rej({ack:{err: Gun.log('Only a node can be linked! Not "' + msg.put + '"!')}} ) }
			gun.put(Gun.obj.put({}, soul, Gun.val.link.ify(soul)), cb, opt);
		},true);
		res({ref:item, ack:{ok:0}});
  }))
}

/*
* Function promOn
* @param callback (function) - function to be called upon changes to data
* @param option (object) - {change: true} only allow changes to trigger the callback
* @return - data and key
* subscribes callback to data
*/

Gun.chain.promOn = async function (callback, option) {
  var gun = this;
  return (new Promise((res, rej)=>{
    gun.on(function (data, key){
      callback(data, key);
      res(data, key);
    }, option);
  }));
}