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javascript promise

let conditions=true;


const proms= new Promise((resolve, reject) => {
    setTimeout(() => {
        if (conditions) {
            resolve ("Hello")
        } else {
            reject ("This condition faild")
        }
    }, 2000);
});


proms.then((result) => {
    console.log(result);
})
.catch(function(error){
    console.log(error);
});

Comment

new promise function

const myPromise = new Promise((resolve, reject) => {
  setTimeout(() => {
    resolve('foo');
  }, 300);
});

myPromise
  .then(handleResolvedA, handleRejectedA)
  .then(handleResolvedB, handleRejectedB)
  .then(handleResolvedC, handleRejectedC);
Comment

javascript promise

var promise = new Promise(function(resolve, reject) {
  // do some long running async thing…
  
  if (/* everything turned out fine */) {
    resolve("Stuff worked!");
  }
  else {
    reject(Error("It broke"));
  }
});

//usage
promise.then(
  function(result) { /* handle a successful result */ },
  function(error) { /* handle an error */ }
);
Comment

what is promise in javascript

Promises are used to handle asynchronous operations in JavaScript.
They are easy to manage when dealing with multiple asynchronous operations
where callbacks can create callback hell leading to unmanageable code.
Comment

javascript promise example basic

const anotherPromise = new Promise((resolve, reject) => {
  setTimeout(() => {
    resolve('this is the eventual value the promise will return');
  }, 300);
});

// CONTINUATION
anotherPromise
.then(value => { console.log(value) })
Comment

javascript promise

let promise = new Promise((resolve,reject)=>{
                try {
                    resolve("some data");
                } catch (error) {
                    reject(error);
                }
            })
            
            promise.then(function (data) {
                console.log(data);
            },function (error) {
                console.error(error);
            })
Comment

promise in javascript

const studentRol=new Promise((resolve, reject) => {
    setTimeout(()=>{
        /**this function will give the value Of tageted studebt Roll number  */
           let RollOffStd=[1,2,3,4,5,6,7,8];
        
            for (let index = RollOffStd[RollOffStd.length-1]+1 ; index <50; index++) {
                RollOffStd.push(index)
                
            }
            
            resolve( RollOffStd)
            
            reject('My name is Noor mohammad ')
      

    },1000)
})


const mybiodata=(gRollOfStudent /* this is First parameter OF ( mybiodata function ) and You can change parameter value  */)=>{
    return new Promise((resolve, reject) => {
        setTimeout((x) => {
           let  bio={
                myname : 'Noor mohammad Patwary ' ,
                age : 25 ,
            }

            resolve(`my name is ${bio.myname } and my age =  ${bio.age } and my roll is =${x} ` )
        }, 1000,gRollOfStudent);
    })
}

studentRol.then(( RollOfStudent)=>{
    console.log(RollOfStudent); /** From here we are gating the Value OF student roll number  */
    mybiodata(RollOfStudent[1] /* this is First Argument OF ( mybiodata function )*/).then((fff)=>{
        console.log(fff);
    })

}).catch((x)=>{
    console.log(x);
})



Comment

promise in javascript

/*
A promise is a building object of JavaScript, using it we can easily do 
asynchronous tasks. Also, the concept that is used to create clean code 
basically promises.
*/
//Promise
let firstPromise = new Promise((resolved, reject) => {
    let fullName = 'Muhammad Shahnewaz';
    setTimeout(() => resolved(fullName), 3000);  //we need to use setTimeout() 
}).then((name) => {
    console.log('I am ' + name);    //Muhammad Shahnewaz
});
Comment

javascript Program with a Promise

const count = true;

let countValue = new Promise(function (resolve, reject) {
    if (count) {
        resolve("There is a count value.");
    } else {
        reject("There is no count value");
    }
});

console.log(countValue);
Comment

promise javascript

let promise = new Promise(function(resolve, reject){
  try{
  	resolve("works"); //if works
  } catch(err){
    reject(err); //doesn't work
  }
}).then(alert, console.log); // if doesn't work, then console.log it, if it does, then alert "works"
Comment

js promise

const executorFunction = (resolve, reject) => {
  if (someCondition) {
      resolve('I resolved!');
  } else {
      reject('I rejected!'); 
  }
}
const myFirstPromise = new Promise(executorFunction);
Comment

Create A Promise In JavaScript

async function abc() 
{ 	
	const myPromise = new Promise(function(resolve, reject) {
   resolve("hello world");
});
let y= await myPromise;
console.log(y);
/*"hello world*/
	}
Comment

javascript promise


const myScore=500 ;

function checkNumnbner() {
    console.log('Course Enrolment Process');
    const myPromise=new Promise((resolve , reject)=>{
        if (myScore >= 80) {
            resolve("First one is true");
        }else{
            setTimeout(() => {
                reject("SORRY we CANT offering you a job")
            }, 2000);
        }
     })
    return myPromise;
    
}

function offerLater() {
    const newPromise2=new Promise((resolve) => {
        setTimeout(() => {
            resolve("congratulation we are offering you a job")
        }, 500);
        
    })
    return newPromise2;
}

function thanksT() {
    const End= new Promise(() => {
        
           setTimeout(()=>{
            console.log(('Thanks to try'));
           },2000)
        
    })
    return End
}

checkNumnbner()
.then(offerLater)
.then(value=> console.log(value))
.then(thanksT)

.catch((error)=>{
    console.log(error);
})
Comment

promise syntax for javascript

let myPromise = new Promise(function(myResolve, myReject) {
// "Producing Code" (May take some time)

  myResolve(); // when successful
  myReject();  // when error
});

// "Consuming Code" (Must wait for a fulfilled Promise)
myPromise.then(
  function(value) { /* code if successful */ },
  function(error) { /* code if some error */ }
);
Comment

promise javascript

/*
Promise is a constructor function, so you need to use the new keyword to 
create one. It takes a function, as its argument, with two parameters - 
resolve and reject. These are methods used to determine the outcome of the
promise. 
The syntax looks like this:
*/

const myPromise = new Promise((resolve, reject) => {

});

Comment

promise javascript

let num = 10;
//call back function
const promis = new Promise(function (resolve, reject) {

  if (num > 5) {

    //this resolve method will send data to resoleveData variable
    resolve(" Problem resolved successfully")
  }
  else {
    //this reject method will send data to rejectData variable
    reject("sorry problem couldn't solve")
  }

})
//resoleveData variable
promis.then(function (resolveData) {

  console.log(resolveData)
  //rejectData variable
}).catch(function (rejectData) {

  console.log(rejectData)
})
Comment

js promise

const prom = new Promise((resolve, reject) => {
  resolve('Yay!');
});
 
const handleSuccess = (resolvedValue) => {
  console.log(resolvedValue);
};
 
prom.then(handleSuccess); // Prints: 'Yay!'
Comment

javascript Create a Promise

let promise = new Promise(function(resolve, reject){
     //do something
});
Comment

javascript promises

var posts = [
  {name:"Mark42",message:"Nice to meet you"},
  {name:"Veronica",message:"I'm everywhere"}
];

function Create_Post(){
  setTimeout(() => {
    posts.forEach((item) => {
      console.log(`${item.name} --- ${item.message}`);
    });
  },1000);
}

function New_Post(add_new_data){
  return new Promise((resolve, reject) => {
    setTimeout(() => {
     posts.push(add_new_data);
      var error = false;
      if(error){
        reject("Something wrong in </>, Try setting me TRUE and check in console");
      }
      else{
        resolve();
      }
    },2000);
  })
}

New_Post({name:"War Machine",message:"I'm here to protect"})
    .then(Create_Post)
    .catch(err => console.log(err));
Comment

promise syntax in js


// make new promise ... so this object will promise us that it will hold an Asynchronous action
// some times promise resolve and some times promise get rejected
const A = new Promise((resolve, reject) => {
    setTimeout(() => {
        // here we pass argument if promise get resolved
        resolve('Done');

        // here we pass argument if promise get rejected
        reject('Didn"t');
    }, 3000);
});


// design handling callback function for resolve 
let handleResolvedA = (massage)=>{console.log(massage)}

// design handling callback function for reject 
let handleRejectedA = (massage)=>{console.log(massage)}


// do handling for both
A.then(handleResolvedA, handleRejectedA)
Comment

js promises

let examplePromise = new Promise(function (resolve, reject) {
  let sum;
  setTimeout(function(){
    sum = 5 + 6;
    if(sum > 10) {
      resolve(sum);
    }else{
      reject('The promise has been rejected');
    }     
  }, 2000);
});
Comment

promise javascript

const promiseA = new Promise( (resolutionFunc,rejectionFunc) => {
    resolutionFunc(777);
});
// At this point, "promiseA" is already settled.
promiseA.then( (val) => console.log("asynchronous logging has val:",val) );
console.log("immediate logging");

// produces output in this order:
// immediate logging
// asynchronous logging has val: 777
Comment

javascript promise

var myImage = document.querySelector('#example');

function loaded() {
  // bien, la imagen cargó
}

if (myImage.complete) {
  loaded();
} else {
  myImage.addEventListener('load', loaded);
}

myImage.addEventListener('error', function() {
  // ocurrió un imprevisto
});
Comment

making promises in js

getData()
    .then(data => console.log(data))
    .catch(error => console.log(error));
Comment

promises in javascript

myPromise.then(
  function(value) { /* code if successful */ },
  function(error) { /* code if some error */ }
);
Comment

js promise

let num = 2;
//call back function
const promis = new Promise(function (resolve, reject) {

  if (num > 5) {

    //this resolve method will send data to resoleveData variable
    resolve(" Problem resolved successfully")
  }
  else {
    //this reject method will send data to rejectData variable
    reject("sorry problem couldn't solve")
  }

})

promis.then(
    //resoleveData variable
    function (resolveData) {

    console.log(resolveData)
    
    }).catch(
    //rejectData variable
    function (rejectData) {

        console.log(rejectData)
    })
Comment

promise definition in javascript

A promise is an object that may produce a single value sometime in the future: either a resolved value, or a reason that it's not resolved (e.g., a network error occurred)
Comment

promise in js

myPromise
.then(handleResolvedA)
.then(handleResolvedB)
.then(handleResolvedC)
.catch(handleRejectedAny)
.finally(handleComplition)
Comment

javascript promises

let dataIsLoading = true;

promise
  .then(data => {
    // do something with data
  })
  .catch(error => {
   // do something with error
  })
  .finally(() => {
    dataIsLoading = false;
  })
Comment

what is promise in javascript

Promises make async javascript easier as they are easy to use and write than callbacks. Basically , promise is just an object , that gives us either success of async opertion or failue of async operations
Comment

javascript promise

const maPromesse = new Promise((resolve, reject) => {
  setTimeout(() => {
    resolve('toto');
  }, 300);
});

maPromesse
  .then(gestionnaireSuccesA, gestionnaireEchecA)
  .then(gestionnaireSuccesB, gestionnaireEchecB)
  .then(gestionnaireSuccesC, gestionnaireEchecC);
Comment

javascript promise example

/* Testing Grepper
Comment

js promise example

function examplePromise(){
  let promiseToReturn = new Promise(function (resolve, reject) {
    let sum;
    setTimeout(function(){
      sum = 5 + 6;
      if(sum > 10) {
        resolve(sum);
      }else{
        reject('The promise has been rejected');
      }     
    }, 2000);
  });
  return promiseToReturn;
}

console.log('some piece of code');
examplePromise().then(function(result){
  console.log(result);
}).catch(function(error){
  console.log(error);
});
console.log('another piece of code');
Comment

JavaScript Promises

// returns a promise
let countValue = new Promise(function (resolve, reject) {
   reject('Promise rejected'); 
});

// executes when promise is resolved successfully
countValue.then(
    function successValue(result) {
        console.log(result); // Promise resolved
    },
 )
Comment

JavaScript Promise Methods

Method	Description
all(iterable)	Waits for all promises to be resolved or any one to be rejected
allSettled(iterable)	Waits until all promises are either resolved or rejected
any(iterable)	Returns the promise value as soon as any one of the promises is fulfilled
race(iterable)	Wait until any of the promises is resolved or rejected
reject(reason)	Returns a new Promise object that is rejected for the given reason
resolve(value)	Returns a new Promise object that is resolved with the given value
catch()	Appends the rejection handler callback
then()	Appends the resolved handler callback
finally()	Appends a handler to the promise
Comment

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