Javascript：在嵌套函数中返回promise

Question

I have this code:

createOrUpdate({
    test: 'test'
}).then((response) => {
    console.log(response);
});

which will expect a createOrUpdate to return a promise. Here is the createOrUpdate function:

function createOrUpdate(requestParams) {

    var options = {};

    return getService('global', function(error, serviceResult) {
        if (error) {
            log.error(error);
            return callback(error, null);
        }

        //...

        return requestPromise(options);
    });

}

I have this getService method that takes some paramaters and a call back. I need to get that return requestPromise(options) to return when createOrUpdate is called, but currently it is not working. I get an error saying I cannot call then on what createOrUpdate returns.

Ideas?

Answer 1

Simple, you need to make getService into a promise returning API .

Otherwise, node-callback taking functions don't return anything and ignore their own return values.

function createOrUpdate(requestParams) {

    var options = {};

    return fromCallback(getService)('global').then(options => 
        requestPromise(options);
    );

}