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/** @license MIT License (c) copyright 2010-2014 original author or authors */
/** @author Brian Cavalier */
/** @author John Hann */
(function(define) { 'use strict';
define(function() {
return function flow(Promise) {
var resolve = Promise.resolve;
var reject = Promise.reject;
var origCatch = Promise.prototype['catch'];
/**
* Handle the ultimate fulfillment value or rejection reason, and assume
* responsibility for all errors. If an error propagates out of result
* or handleFatalError, it will be rethrown to the host, resulting in a
* loud stack track on most platforms and a crash on some.
* @param {function?} onResult
* @param {function?} onError
* @returns {undefined}
*/
Promise.prototype.done = function(onResult, onError) {
this._handler.visit(this._handler.receiver, onResult, onError);
};
/**
* Add Error-type and predicate matching to catch. Examples:
* promise.catch(TypeError, handleTypeError)
* .catch(predicate, handleMatchedErrors)
* .catch(handleRemainingErrors)
* @param onRejected
* @returns {*}
*/
Promise.prototype['catch'] = Promise.prototype.otherwise = function(onRejected) {
if (arguments.length < 2) {
return origCatch.call(this, onRejected);
}
if(typeof onRejected !== 'function') {
return this.ensure(rejectInvalidPredicate);
}
return origCatch.call(this, createCatchFilter(arguments[1], onRejected));
};
/**
* Wraps the provided catch handler, so that it will only be called
* if the predicate evaluates truthy
* @param {?function} handler
* @param {function} predicate
* @returns {function} conditional catch handler
*/
function createCatchFilter(handler, predicate) {
return function(e) {
return evaluatePredicate(e, predicate)
? handler.call(this, e)
: reject(e);
};
}
/**
* Ensures that onFulfilledOrRejected will be called regardless of whether
* this promise is fulfilled or rejected. onFulfilledOrRejected WILL NOT
* receive the promises' value or reason. Any returned value will be disregarded.
* onFulfilledOrRejected may throw or return a rejected promise to signal
* an additional error.
* @param {function} handler handler to be called regardless of
* fulfillment or rejection
* @returns {Promise}
*/
Promise.prototype['finally'] = Promise.prototype.ensure = function(handler) {
if(typeof handler !== 'function') {
return this;
}
return this.then(function(x) {
return runSideEffect(handler, this, identity, x);
}, function(e) {
return runSideEffect(handler, this, reject, e);
});
};
function runSideEffect (handler, thisArg, propagate, value) {
var result = handler.call(thisArg);
return maybeThenable(result)
? propagateValue(result, propagate, value)
: propagate(value);
}
function propagateValue (result, propagate, x) {
return resolve(result).then(function () {
return propagate(x);
});
}
/**
* Recover from a failure by returning a defaultValue. If defaultValue
* is a promise, it's fulfillment value will be used. If defaultValue is
* a promise that rejects, the returned promise will reject with the
* same reason.
* @param {*} defaultValue
* @returns {Promise} new promise
*/
Promise.prototype['else'] = Promise.prototype.orElse = function(defaultValue) {
return this.then(void 0, function() {
return defaultValue;
});
};
/**
* Shortcut for .then(function() { return value; })
* @param {*} value
* @return {Promise} a promise that:
* - is fulfilled if value is not a promise, or
* - if value is a promise, will fulfill with its value, or reject
* with its reason.
*/
Promise.prototype['yield'] = function(value) {
return this.then(function() {
return value;
});
};
/**
* Runs a side effect when this promise fulfills, without changing the
* fulfillment value.
* @param {function} onFulfilledSideEffect
* @returns {Promise}
*/
Promise.prototype.tap = function(onFulfilledSideEffect) {
return this.then(onFulfilledSideEffect)['yield'](this);
};
return Promise;
};
function rejectInvalidPredicate() {
throw new TypeError('catch predicate must be a function');
}
function evaluatePredicate(e, predicate) {
return isError(predicate) ? e instanceof predicate : predicate(e);
}
function isError(predicate) {
return predicate === Error
|| (predicate != null && predicate.prototype instanceof Error);
}
function maybeThenable(x) {
return (typeof x === 'object' || typeof x === 'function') && x !== null;
}
function identity(x) {
return x;
}
});
}(typeof define === 'function' && define.amd ? define : function(factory) { module.exports = factory(); }));
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