reduce.js
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"use strict";
module.exports = function(Promise,
PromiseArray,
apiRejection,
tryConvertToPromise,
INTERNAL) {
var util = require("./util.js");
var tryCatch = util.tryCatch;
var errorObj = util.errorObj;
function ReductionPromiseArray(promises, fn, accum, _each) {
this.constructor$(promises);
this._promise._captureStackTrace();
this._preservedValues = _each === INTERNAL ? [] : null;
this._zerothIsAccum = (accum === undefined);
this._gotAccum = false;
this._reducingIndex = (this._zerothIsAccum ? 1 : 0);
this._valuesPhase = undefined;
var maybePromise = tryConvertToPromise(accum, this._promise);
var rejected = false;
var isPromise = maybePromise instanceof Promise;
if (isPromise) {
maybePromise = maybePromise._target();
if (maybePromise._isPending()) {
maybePromise._proxyPromiseArray(this, -1);
} else if (maybePromise._isFulfilled()) {
accum = maybePromise._value();
this._gotAccum = true;
} else {
this._reject(maybePromise._reason());
rejected = true;
}
}
if (!(isPromise || this._zerothIsAccum)) this._gotAccum = true;
this._callback = fn;
this._accum = accum;
if (!rejected) this._init$(undefined, -5);
}
util.inherits(ReductionPromiseArray, PromiseArray);
ReductionPromiseArray.prototype._init = function () {};
ReductionPromiseArray.prototype._resolveEmptyArray = function () {
if (this._gotAccum || this._zerothIsAccum) {
this._resolve(this._preservedValues !== null
? [] : this._accum);
}
};
ReductionPromiseArray.prototype._promiseFulfilled = function (value, index) {
var values = this._values;
values[index] = value;
var length = this.length();
var preservedValues = this._preservedValues;
var isEach = preservedValues !== null;
var gotAccum = this._gotAccum;
var valuesPhase = this._valuesPhase;
var valuesPhaseIndex;
if (!valuesPhase) {
valuesPhase = this._valuesPhase = new Array(length);
for (valuesPhaseIndex=0; valuesPhaseIndex<length; ++valuesPhaseIndex) {
valuesPhase[valuesPhaseIndex] = 0;
}
}
valuesPhaseIndex = valuesPhase[index];
if (index === 0 && this._zerothIsAccum) {
this._accum = value;
this._gotAccum = gotAccum = true;
valuesPhase[index] = ((valuesPhaseIndex === 0)
? 1 : 2);
} else if (index === -1) {
this._accum = value;
this._gotAccum = gotAccum = true;
} else {
if (valuesPhaseIndex === 0) {
valuesPhase[index] = 1;
} else {
valuesPhase[index] = 2;
this._accum = value;
}
}
if (!gotAccum) return;
var callback = this._callback;
var receiver = this._promise._boundTo;
var ret;
for (var i = this._reducingIndex; i < length; ++i) {
valuesPhaseIndex = valuesPhase[i];
if (valuesPhaseIndex === 2) {
this._reducingIndex = i + 1;
continue;
}
if (valuesPhaseIndex !== 1) return;
value = values[i];
this._promise._pushContext();
if (isEach) {
preservedValues.push(value);
ret = tryCatch(callback).call(receiver, value, i, length);
}
else {
ret = tryCatch(callback)
.call(receiver, this._accum, value, i, length);
}
this._promise._popContext();
if (ret === errorObj) return this._reject(ret.e);
var maybePromise = tryConvertToPromise(ret, this._promise);
if (maybePromise instanceof Promise) {
maybePromise = maybePromise._target();
if (maybePromise._isPending()) {
valuesPhase[i] = 4;
return maybePromise._proxyPromiseArray(this, i);
} else if (maybePromise._isFulfilled()) {
ret = maybePromise._value();
} else {
return this._reject(maybePromise._reason());
}
}
this._reducingIndex = i + 1;
this._accum = ret;
}
this._resolve(isEach ? preservedValues : this._accum);
};
function reduce(promises, fn, initialValue, _each) {
if (typeof fn !== "function") return apiRejection("fn must be a function\u000a\u000a See http://goo.gl/916lJJ\u000a");
var array = new ReductionPromiseArray(promises, fn, initialValue, _each);
return array.promise();
}
Promise.prototype.reduce = function (fn, initialValue) {
return reduce(this, fn, initialValue, null);
};
Promise.reduce = function (promises, fn, initialValue, _each) {
return reduce(promises, fn, initialValue, _each);
};
};