Promise.all In Node Is Undefined

I'm playing around with promises in Node.js and am trying to use Promise.all. I'm pushing three functions that return a promise into an array and then calling Promise.all but the a

Solution 1:

That's strange because I have Promise.all defined even on old Node 0.12. On Node 0.10 I have Promise not defined. I don't think there's a version with Promise but without Promise.all. Maybe you're doing:

Promise.all = undefined;

What you should have undefined is the resolve function. Here:

Promise.all(updates).then(function (success) {
    resolve("Item successfully used");
}, function (error) {
    resolve("Failed to use item " + error.toString());
});

you don't have any resolve to call. Don't you mean console.log?

Promise.all(updates).then(function (success) {
    console.log("Item successfully used");
}, function (error) {
    console.log("Failed to use item " + error.toString());
});

Also here:

data.updateSharedLoot= function (lootUpdateChange) {
    returnnewPromise(function (resolve, reject) {
        //some logic
        io.writeFile(...,function(callbackSuccess){
            resolve(callbackSuccess);
        });
    });
}

the first parameter to your callback is probably an error, so you should:

data.updateSharedLoot= function (lootUpdateChange) {
    returnnewPromise(function (resolve, reject) {
        //some logic
        io.writeFile(...,function(error, callbackSuccess) {
            if (error) {
                reject(error);
            } else {
                resolve(callbackSuccess);
            }
        });
    });
}

But still I would suggest using a promised version of I/O like fs-promise if you're doing promises anyway. Your function that returns a promise could be as simple as:

var fsp = require('fs-promise');

data.updateSharedLoot = function (lootUpdateChange) {
    return fsp.writeFile(...);
};

See this answer for more details.