@perymimon/tiny-promise v1.0.2

Tiny Promise

TP is Tiny (1.5kb minefield) is implementation of Promises/A+ spec by using ec5 js only. It's an agnostic, cross-browser and very lightweight library to polyfill native promise and it simple enough to extend it with more features

Browser Compatibility

TP is compatible with the following browsers/versions:

• Google Chrome
• Firefox
• Safari
• IOS Safari
• Opera
• IE 7+

Spec

spec's test come from Promises/A+ Compliance Test Suite

API & Usage

constructor

const promise = TP(function init( resolve, reject ){
    //some code that call resolve or reject at some point 
}) 

 // define new promise that fulified after two seconds
var promise1 = new TP(function (res, rej){
    setTimeout(function() {
      res('go on');
    }, 2000);
})

promise

const newPromise = promise.then( fulifiedCallback ( value ){} , rejectCallback(reson){})

const newPromise = promise.catch( rejectCallback(reson){} )

promise.status // return the status of the promise can be:  'pending', 'reject', 'resolve'      
    
promise.value // return the value of the promise can come from resolve or reject
 

example

// then return new value that depend on the fulified value 
var promise2 = promise1
  
.then(function fulifiedCallback(value) {
    console.log(value); // echo 'go on'
    return value + ' again';
})

// do somthing with the new value but expetion are happend so new promise rejected
.then(function (value) {
    console.log(value); // echo 'go on again'
    throw 'what"s happen???'
})

// catch the expection and do somthing with it
.catch(function(err) {
    console.log(err); // 'what"s happen???'
    return 'every thing ok now' 
})

// after that promise are ok again
.then (function (value){
    console.log(value); // 'every thing ok now'
})

// the value that return can be promise, so what happen next depend on the status of the promise
.then( function (value){

    return TP.reject( 'sorry, it just happen' ) 
})

.catch(function rejectCallback(err) {
        console.log(err); // 'sorry, it just happen'
        return 'every thing ok now' 
}) 

// the value that return can be even *thentable*, so now the object that you write can decide what happen next 
.then( function (value){
    return {
        then:function(res, rej){
            Math.random()>0.5> res('ye'), rej('ho no')            
        } 
}).then( function onFullified(value){
    console.log(value) // 'ye'
},function onReject(reason){
    console.log( reason ) // 'ho no'
})     

Static functions

TP.all([promise1, promise2, ...] )
.then(function onAllFilied(values){
    promise1Value = value[0];
    promise2Value = value[1];
    ...
},function someReject(reason){
    // when one of the promises rejected
})

TP.race([promise1, promise2, ...] )
.then(
    function whenFirstPromiseResolve(value){},
    function orWhenFirstPromiseReject(reason){}
)

rejectedPromise = TP.reject(reason);

resolvedPromise = TP.resolve(value);

{promise, resolve, reject} = TP.deferred();