Javascript 承诺错误表示 .then() 未定义。 异步

Question

This is probably a simple question with a simple answer, but I am not very experienced with this sort of stuff. It is saying that .then() is not defined in this code. Thanks in advance. Here is my code:

 const Mypromise = num => { new Promise( function(resolve, reject) { if (num === 0) { resolve('Zero was inputted') } else { reject('You put in a number other than zero') }}) } // const num = () => Math.floor(Math.random() *2) const handleSuccess = handleResolve => {console.log(handleResolve)}; const handleFailure = handleReject => {console.log(handleReject);} Mypromise(5 ).then(handleSuccess).catch(handleFailure);

The error will be seen when you run the code snippet. Could someone tell me how to fix this?

Answer 1

You need to return your Promise , otherwise, you're returning undefined (which doesn't have a property/function called then ).

 const Mypromise = num => { // return the Promise return new Promise(function(resolve, reject) { if (num === 0) { resolve('Zero was inputted') } else { reject('You put in a number other than zero') } }) } // const num = () => Math.floor(Math.random() *2) const handleSuccess = handleResolve => { console.log(handleResolve) }; const handleFailure = handleReject => { console.log(handleReject); } Mypromise(5).then(handleSuccess).catch(handleFailure);