Salesforce Lightning JavaScript Helper method that returns a Promise when calling an Apex Controller method

promiseAction.js

promiseAction : function(cmp, methodName, params){
    console.log(methodName);
    console.log(params);
    return new Promise(function(resolve, reject) {     
        var action = cmp.get(methodName); 
        action.setParams(params);   
        action.setCallback(this, function(response) {
            var state = response.getState();
            console.log(methodName + ' ' + state);
            if(cmp.isValid() && state === "SUCCESS"){
                var result = response.getReturnValue();
                console.log(result);
                resolve(result);
            } else if (state === "ERROR"){
                var errors = response.getError();
                if (errors) {
                    if (errors[0] && errors[0].message) {
                        console.log(methodName + ': ' + errors[0].message);
                    }
                }
                reject(errors);
            }
        });
        $A.getCallback(function() {
            $A.enqueueAction(action); 
        })(); 
    }); 
},