return function(units, destinations, onePerDestination) {
var distancesByUnit = {},
destinationsByUnit = {},
minDistanceByUnit,
dis2des,
destinationsLeft,
unitsLeft;
if (!units || !destinations) {
return {};
}
if (onePerDestination === undefined) {
onePerDestination = true;
}
destinationsLeft = destinations.length;
unitsLeft = units.length;
if (destinationsLeft === 0 || unitsLeft === 0) {
return {};
}
//Get all distances
_.each(units, function(u) {
distancesByUnit[u.id] = [];
_.each(destinations, function(d) {
distancesByUnit[u.id].push({
destination: d,
unit: u,
distance: getDistance(u, d)
});
});
});
minDistanceByUnit = getMinDistanceByUnit(distancesByUnit);
while (unitsLeft > 0 &&
(!onePerDestination || destinationsLeft > 0)) {
dis2des = _.min(minDistanceByUnit, 'distance');
destinationsByUnit[dis2des.unit.id] = dis2des.destination;
delete distancesByUnit[dis2des.unit.id];
unitsLeft--;
if (onePerDestination) {
_.each(distancesByUnit,
removeDestination(dis2des.destination));
destinationsLeft--;
}
minDistanceByUnit = getMinDistanceByUnit(distancesByUnit);
}
return destinationsByUnit;
};
work: function() {
winston.info('manager:composeResponse');
// Update the expiration date on the bundle
var tout = {
expires: _.min( thisResponse, function( val ) { return val.expires } ).expires,
lastModified: now
};
if (_.has( thisResponse, 'redirect')) {
tout.redirect = thisResponse.redirect,
tout.guid = thisResponse.guid,
tout.authBundle = thisResponse.authBundle,
tout.authPart = thisResponse.authPart
};
// Insert api responses into bundle
_.each( thisResponse, function( val, idx ) {
tout[val.cname] = val;
});
// Perform cleanup function on bundle
if (_.has(bundle, 'cleanup')) {
tout = bundle.cleanup(tout);
}
// Determine the seconds left before expiry
if ( 'expires' in tout && _.isDate(tout.expires) ) {
tout.secleft = tout.expires.getSecondsBetween( now ) * -1;
} else {
tout.secleft = 3600;
}
// Save cached bundle in Redis
client.set('bid'+bid, JSON.stringify(tout));
manager.enqueue('sendResponse', tout);
this.finished = true;
}
// invoke: 在list里的每个元素上调用名为methodName的函数,任何附加的函数传入，invoke将会转给调用的函数
var v = _.invoke([[2,1,3], [4,5,2]], 'sort')
console.log("v", v);
// pluck: 提取一个集合里指定的属性值
var users = [
{name:'moe', age: 40},
{name:'larry', age: 50}
];
console.log(_.pluck(users, 'name'));
// max, min, sortBy：取list中的最大，最小元素，自定义比较器
console.log(_.max(users, function(stooge){
return stooge.age
}));
console.log(_.min(users, function(stooge){
return stooge.age //{ name: 'moe', age: 40 }
}));
console.log(_.sortBy([3,4,1,2,6], function(num){
return Math.max(num);//[ 1, 2, 3, 4, 6 ]
}));
// groupBy 一个集合分成多个集合
console.log(_.groupBy(['one', 'two', 'three'], 'length'));//{ '3': [ 'one', 'two' ], '5': [ 'three' ] }
// size 得到list中元素个数
console.log(_.size({one:1, two:2, three: 3})); //3
// shuffle：随机打乱一个数据
console.log(_.shuffle([1,2,3,4,5,6,7]));
// countBy 把一个数据分组后计数
console.log(_.countBy([1,2,3,4,5], function(num){
return num % 2 == 0 ? 'even':'odd'; //{ odd: 3, even: 2 }
}));
Helpers.prototype.getRange = function(array) {
return _.max(array) - _.min(array);
}
_.each(distancesByUnit, function(dis2desArray, unitID) {
minDistanceByUnit[unitID] = _.min(dis2desArray, 'distance');
});