'use strict';
var Promise = require('./promise');
var getArguments = require('argsarray');
var once = require('./once');
function toPromise(func) {
//create the function we will be returning
return getArguments(function (args) {
var self = this;
var tempCB =
(typeof args[args.length - 1] === 'function') ? args.pop() : false;
// if the last argument is a function, assume its a callback
var usedCB;
if (tempCB) {
// if it was a callback, create a new callback which calls it,
// but do so async so we don't trap any errors
usedCB = function (err, resp) {
process.nextTick(function () {
tempCB(err, resp);
});
};
}
var promise = new Promise(function (fulfill, reject) {
var resp;
try {
var callback = once(function (err, mesg) {
if (err) {
reject(err);
} else {
fulfill(mesg);
}
});
// create a callback for this invocation
// apply the function in the orig context
args.push(callback);
resp = func.apply(self, args);
if (resp && typeof resp.then === 'function') {
fulfill(resp);
}
} catch (e) {
reject(e);
}
});
// if there is a callback, call it back
if (usedCB) {
promise.then(function (result) {
usedCB(null, result);
}, usedCB);
}
return promise;
});
}
module.exports = toPromise; |