Promises in Javascript

Author: kanaklatwal

09_advance_one/promises/promises.js

@@ -0,0 +1,103 @@
+//fetch('https://somthjing.com').then().catch().finally()
+const promiseOne = new Promise(function(resolve, reject){
+    //Do an async task
+    // DB calls, cryptography, network
+    setTimeout(function(){
+        console.log('Async task is complete');
+        resolve()
+    }, 1000)
+})
+//Async task is complete
+//Promise consumed
+
+promiseOne.then(function(){
+    console.log("Promise consumed");
+})
+
+new Promise(function(resolve, reject){
+    setTimeout(function(){
+        console.log("Async task 2");
+        resolve();
+    },1000)
+}).then(function(){
+    console.log("Async 2 resolved");
+})
+// Async task 2
+// Async 2 resolved
+
+const promiseThree = new Promise(function(resolve, reject){
+    setTimeout(function(){
+       resolve({username: "Chai", email: "chai@example.com"})
+    }, 1000)
+})
+
+promiseThree.then(function(user){
+    console.log(user);//{ username: 'Chai', email: 'chai@example.com' }
+})
+
+const promiseFour = new Promise(function(resolve, reject){
+    setTimeout(function(){
+        let error = true;
+        if(!error){
+            resolve({username: "kassh", password: "123"});
+        }else{
+            reject('ERROR: Something went wrong');
+        }
+    },1000)
+})
+
+promiseFour.then((user) =>{
+     console.log(user);
+     return user.username
+})
+.then((username)=>{
+       console.log(username);
+})
+.catch(function(error){
+       console.log(error)
+}).finally(() => console.log("The promise is either resolved or rejected"))
+
+
+
+const promiseFive = new Promise(function (resolve, reject){
+    setTimeout(function(){
+        let error = true;
+        if(!error){
+            resolve({username: "javascript", password: "123"});
+        }else{
+            reject('ERROR: JS went wrong');
+        }
+    },1000)
+});
+
+async function consumePromiseFive(){
+    try{
+        const response = await promiseFive
+        console.log(response);
+    }catch(error){
+        console.log(error); 
+    }
+}
+
+consumePromiseFive()
+
+
+// async function getAllUsers(){
+//     try{
+//         const response = await fetch('https://jsonplaceholder.typicode.com/users')
+//         const data = await response.json()
+//         console.log(data);
+//     }catch(error){
+//         console.log("E: ", error);
+//     }
+// }
+// getAllUsers()
+
+fetch('https://jsonplaceholder.typicode.com/users')
+.then((response)=>{
+       return response.json()
+})
+.then((data) => {
+       console.log(data);
+})
+.catch((error) => console.log(error))