how to make a promise js code example
Example 1: js create a promise
let promise = new Promise((resolve , reject) => {
fetch("https://myAPI")
.then((res) => {
resolve(res);
})
.catch((err) => {
reject(err);
});
});
Example 2: 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));
Example 3: javascript promises
firstRequest()
.then(function(response) {
return secondRequest(response);
}).then(function(nextResponse) {
return thirdRequest(nextResponse);
}).then(function(finalResponse) {
console.log('Final response: ' + finalResponse);
}).catch(failureCallback);