Promises - ES6
A promise represents a single asynchronous operation. ES2015 provides a pattern/method to declare an operation that hasn’t been completed but is expected to be completed.
The simplest way to demonstate this is via a setTimeout() method
. Take the following example:
function waitOneMoment() {
return new Promise(
(resolve, reject)=> {
setTimeout(
()=> resolve('break over'),
5000
);
}
)
}
var test = waitOneMoment()
.then(
(res)=> {
console.log(res);
},
(reason)=> {
console.log(reason);
}
);
In the above example we call the function waitOneMoment
, which returns a Promise
that will either resolve
or reject
(ommitted from example) the promise. Then
is a fulfilment handler which will return a resolved or rejected value.
TODO - Show examples of all methods/prototypes/examples of breaking promises.