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Added unhanded rejection warnings. Updated version to 4.0.1
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taylorhakes committed Mar 19, 2016
1 parent 2f8e889 commit c381e1f
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8 changes: 8 additions & 0 deletions README.md
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Expand Up @@ -66,6 +66,14 @@ var setAsap = require('setasap');
Promise._setImmedateFn(setAsap);
```

## Unhandled Rejections
promise-polyfill will warn you about possibly unhandled rejections. It will show a console warning if a Promise is rejected, but no `.catch` is used. You can turn off this behavior by setting `Promise._setUnhandledRejectionFn(<rejectError>)`.
If you would like to disable unhandled rejections. Use a noop like below.
```js
Promise._setUnhandledRejectionFn(function(rejectError) {});
```


## Testing
```
npm install
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4 changes: 2 additions & 2 deletions package.json
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@@ -1,11 +1,11 @@
{
"name": "promise-polyfill",
"version": "4.0.0",
"version": "4.0.1",
"description": "Lightweight promise polyfill. A+ compliant",
"main": "Promise.js",
"scripts": {
"test": "eslint promise.js && mocha && karma start --single-run",
"build": "uglifyjs --compress --mangle -o Promise.min.js -- Promise.js "
"build": "uglifyjs --compress --mangle -o promise.min.js -- promise.js "
},
"repository": {
"type": "git",
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230 changes: 230 additions & 0 deletions promise.js
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@@ -0,0 +1,230 @@
(function (root) {

// Store setTimeout reference so promise-polyfill will be unaffected by
// other code modifying setTimeout (like sinon.useFakeTimers())
var setTimeoutFunc = setTimeout;

function noop() {
}

// Use polyfill for setImmediate for performance gains
var asap = (typeof setImmediate === 'function' && setImmediate) ||
function (fn) {
setTimeoutFunc(fn, 1);
};

var onUnhandledRejection = function onUnhandledRejection(err) {
console.warn('Possible Unhandled Promise Rejection:', err); // eslint-disable-line no-console
};

// Polyfill for Function.prototype.bind
function bind(fn, thisArg) {
return function () {
fn.apply(thisArg, arguments);
};
}

var isArray = Array.isArray || function (value) {
return Object.prototype.toString.call(value) === '[object Array]';
};

function Promise(fn) {
if (typeof this !== 'object') throw new TypeError('Promises must be constructed via new');
if (typeof fn !== 'function') throw new TypeError('not a function');
this._state = 0;
this._handled = false;
this._value = undefined;
this._deferreds = [];

doResolve(fn, this);
}

function handle(self, deferred) {
while (self._state === 3) {
self = self._value;
}
if (self._state === 0) {
self._deferreds.push(deferred);
return;
}
self._handled = true;
asap(function () {
var cb = self._state === 1 ? deferred.onFulfilled : deferred.onRejected;
if (cb === null) {
(self._state === 1 ? resolve : reject)(deferred.promise, self._value);
return;
}
var ret;
try {
ret = cb(self._value);
} catch (e) {
reject(deferred.promise, e);
return;
}
resolve(deferred.promise, ret);
});
}

function resolve(self, newValue) {
try {
// Promise Resolution Procedure: https://github.com/promises-aplus/promises-spec#the-promise-resolution-procedure
if (newValue === self) throw new TypeError('A promise cannot be resolved with itself.');
if (newValue && (typeof newValue === 'object' || typeof newValue === 'function')) {
var then = newValue.then;
if (newValue instanceof Promise) {
self._state = 3;
self._value = newValue;
finale(self);
return;
} else if (typeof then === 'function') {
doResolve(bind(then, newValue), self);
return;
}
}
self._state = 1;
self._value = newValue;
finale(self);
} catch (e) {
reject(self, e);
}
}

function reject(self, newValue) {
self._state = 2;
self._value = newValue;
finale(self);
}

function finale(self) {
if (self._state === 2 && self._deferreds.length === 0) {
setTimeout(function() {
if (!self._handled) {
onUnhandledRejection(self._value);
}
}, 1);
}

for (var i = 0, len = self._deferreds.length; i < len; i++) {
handle(self, self._deferreds[i]);
}
self._deferreds = null;
}

function Handler(onFulfilled, onRejected, promise) {
this.onFulfilled = typeof onFulfilled === 'function' ? onFulfilled : null;
this.onRejected = typeof onRejected === 'function' ? onRejected : null;
this.promise = promise;
}

/**
* Take a potentially misbehaving resolver function and make sure
* onFulfilled and onRejected are only called once.
*
* Makes no guarantees about asynchrony.
*/
function doResolve(fn, self) {
var done = false;
try {
fn(function (value) {
if (done) return;
done = true;
resolve(self, value);
}, function (reason) {
if (done) return;
done = true;
reject(self, reason);
});
} catch (ex) {
if (done) return;
done = true;
reject(self, ex);
}
}

Promise.prototype['catch'] = function (onRejected) {
return this.then(null, onRejected);
};

Promise.prototype.then = function (onFulfilled, onRejected) {
var prom = new Promise(noop);
handle(this, new Handler(onFulfilled, onRejected, prom));
return prom;
};

Promise.all = function () {
var args = Array.prototype.slice.call(arguments.length === 1 && isArray(arguments[0]) ? arguments[0] : arguments);

return new Promise(function (resolve, reject) {
if (args.length === 0) return resolve([]);
var remaining = args.length;

function res(i, val) {
try {
if (val && (typeof val === 'object' || typeof val === 'function')) {
var then = val.then;
if (typeof then === 'function') {
then.call(val, function (val) {
res(i, val);
}, reject);
return;
}
}
args[i] = val;
if (--remaining === 0) {
resolve(args);
}
} catch (ex) {
reject(ex);
}
}

for (var i = 0; i < args.length; i++) {
res(i, args[i]);
}
});
};

Promise.resolve = function (value) {
if (value && typeof value === 'object' && value.constructor === Promise) {
return value;
}

return new Promise(function (resolve) {
resolve(value);
});
};

Promise.reject = function (value) {
return new Promise(function (resolve, reject) {
reject(value);
});
};

Promise.race = function (values) {
return new Promise(function (resolve, reject) {
for (var i = 0, len = values.length; i < len; i++) {
values[i].then(resolve, reject);
}
});
};

/**
* Set the immediate function to execute callbacks
* @param fn {function} Function to execute
* @private
*/
Promise._setImmediateFn = function _setImmediateFn(fn) {
asap = fn;
};

Promise._setUnhandledRejectionFn = function _setUnhandledRejectionFn(fn) {
onUnhandledRejection = fn;
};

if (typeof module !== 'undefined' && module.exports) {
module.exports = Promise;
} else if (!root.Promise) {
root.Promise = Promise;
}

})(this);
1 change: 1 addition & 0 deletions promise.min.js

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2 changes: 1 addition & 1 deletion test/adapter.js
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Expand Up @@ -11,4 +11,4 @@ module.exports = {
obj.promise = prom;
return obj;
}
}
};
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