Promise defer in blue bird

Question

I started to use bluebird instead of Q

Currently the code which I use is like following

runProcess = function(path) {

    var result = Promise.defer();

    fs.readFileAsync(path)
    .then(function (Content) {
            var parser = new parseFile(Content);
            var adpt = parser.update();
            result.resolve(adpt);
    }, function(error) {
            result.reject(error);
    });
    return result.promise;
}

My Question if there a better way to write it ?

Beter as in, shorter / more performant / more readable.. ? Please specify. — Caramiriel, Jan 28 '16 at 08:34
Also, if you make a new promise which you do not need to do here, you should use the ES6 standard way which is `p = new Promise(function(resolve, reject) {...});` — jfriend00, Jan 28 '16 at 08:40
one liner `runProcess = path => fs.readFileAsync(path).then(content => (new parseFile(content)).update());` - perfectly readable - maybe not — Jaromanda X, Jan 28 '16 at 08:42

score 1 · Accepted Answer · edited May 23 '17 at 11:59

1

yes, it can be improved,

step1: stop wrapping promises with promises:

runProcess = function(path) {
   return fs.readFileAsync(path)
    .then(function (Content) {
          var parser = new parseFile(Content);
          return parser.update();
    });
}

Read about this Promise anti-pattern

In really short ES6 form, it might be:

runProcess = path => fs.readFileAsync(path)
                      .then( content => (new parseFile(content )).update())

edited May 23 '17 at 11:59

Community

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answered Jan 28 '16 at 08:36

mido

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to go with convention, `content` not `Content` - as I said, convention, but it's a nice convention – Jaromanda X Jan 28 '16 at 08:43
@JaromandaX valid point, updated :) – mido Jan 28 '16 at 08:44

Promise defer in blue bird

1 Answers1