找到一个类似的属性然后循环对象

Question

I have two objects, car and truck. Each car and truck will have a number property attached to it. However, each car can have multiple trucks related to it but only one truck number will also match the car number.

Example:

car
{
    number: 1054
}

truck
[{
    number: 80,
    type: "pickup",
},{
    number: 1054,
    type: "extended cab"
}, {
    number: 50,
    type: "flatbed"
}]

I would like to see if there's a way to skip having a nested loop by checking to see if they share a number property and if so, then I would like to get the properties attached to it.

Currently I am using slightly more complicated code than below but the idea is that the user is working with one car already when they are looking for the related truck so the first loop below is simplified but the idea is the same.

for (let i = 0; i < cars.length; i++) {
    car1 = cars[0].number;

    for (let j = 0; j < trucks.length; j++) {
        if (car1 === trucks[j].number) {
            console.log('Found matching truck');
        }
     }
}

I would like to know if there is a less taxing way than this or if this is what I should stick to.

I am open to using plain javascript or lodash.

Answer 1

You could use a hash table and the simply look up the number of the car.

 var trucks = [{ number: 80, type: "pickup" }, { number: 1054, type: "extended cab" }, { number: 50, type: "flatbed" }], hash = {}; trucks.forEach(function (truck) { hash[truck.number] = truck; }); console.log(hash[1054]); console.log(hash); 

 .as-console-wrapper { max-height: 100% !important; top: 0; } 

Answer 2

Sure you can use lodash for it

https://lodash.com/docs/4.17.2#

You can use it like that:

_.forEach(cars, function(car) {
  var myTruck = _.find(trucks, function(truck) { return truck.number === car number; });
  if(myTruck === undefined)
    {
       console.log('not found');
    }
  //do what you like with it
});