Skip to content
Related Articles

Related Articles

Improve Article
Save Article
Like Article

JavaScript | promise resolve() Method

  • Last Updated : 27 Jan, 2022

The Promise is an object that represents either completion or failure of a user task. A promise in JavaScript can be in three states pending, fulfilled or rejected. 
The main advantage of using a Promise in JavaScript is that a user can assign callback functions to the promises in case of a rejection or fulfillment of Promise, also by using promises one can easily handle the control flow of all the Asynchronous events or data upcoming. As the name suggests a promise is either kept or broken. So, a promise is either completed(kept) or rejected(broken).
Promise resolve() method: 
Promise.resolve() method in JS returns a Promise object that is resolved with a given value. Any of the three things can happened: 

  • If the value is a promise then promise is returned.
  • If the value has a “then” attached to the promise, then the returned promise will follow that “then” to till the final state.
  • The promise fulfilled with its value will be returned.

Syntax: 

Promise.resolve(value);

Parameters: 
Value(s) to be resolved by this Promise.
Return Value: 
Either the promise of the promise fulfilled with its value is returned.
Examples:  

javascript




<script>
    var promise = Promise.resolve(17468);
 
promise.then(function(val) {
    console.log(val);
});
//Output: 17468
</script>

Output: 

17468

The above example is made using old version approach we may also use the newest arrow function based approach and also try to avoid writing var datatype since it may mix up several other variables and may produce incorrect result. Below is the shortest approach for the above stated approach.

Following is the code snippet which shows the other version of the above illustrated approach-

Javascript




Promise.resolve(17468).then((value) => console.log(value));
 
// This code is contributed by Aman Singla....

Output:

17468

Resolving an array:  Here in the below example, we will be using a timer function called setTimeout() will be responsible for the execution of the values which are passed inside resolve() which is passed inside that timer function.

javascript




<script>
 
    const promise = new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve([89, 45, 323]);
        }, 5000);
    });
 
promise.then(values => {
    console.log(values[1]);
});
 
</script>

Output: 

45 

Resolving another Promise: In below example we will be resolving the first promise inside another newly created promise in which we have defined one timer function (setTimeout).

javascript




<script>
 
    const promise = Promise.resolve(3126);
 
const promise1 = new Promise((resolve, reject) => {
    setTimeout(() => {
        promise.then(val => console.log(val));
    }, 5000);
});
 
promise1.then(vals => {
    console.log(vals);
});
 
</script>

Output: 

3126 

Supported Browsers: 

  • Google Chrome 6.0 and above
  • Internet Explorer 9.0 and above
  • Mozilla 4.0 and above
  • Opera 11.1 and above
  • Safari 5.0 and above

JavaScript is best known for web page development but it is also used in a variety of non-browser environments. You can learn JavaScript from the ground up by following this JavaScript Tutorial and JavaScript Examples.


My Personal Notes arrow_drop_up
Recommended Articles
Page :

Start Your Coding Journey Now!