Is it possible to imitate this database behavior in Javascript?-CodePudding

I'm doing a Javascript test (I'm nowhere near an expert in the matter, I'm much more experienced in Java) and I'm just completely lost, given these declarations:

Number 1

const paddockType = [
    { id: 1, name: 'PALTOS' },
    { id: 2, name: 'AVELLANOS' },
    { id: 3, name: 'CEREZAS' },
    { id: 4, name: 'NOGALES' },
  ]

Number 2

const paddocks = [
    { paddockManagerId: 6, farmId: 1, paddockTypeId: 1, harvestYear: 2019, area: 1200 },
    { paddockManagerId: 1, farmId: 3, paddockTypeId: 4, harvestYear: 2019, area: 500 },
    { paddockManagerId: 5, farmId: 3, paddockTypeId: 2, harvestYear: 2020, area: 20000 },
    { paddockManagerId: 2, farmId: 2, paddockTypeId: 3, harvestYear: 2021, area: 8401},
    { paddockManagerId: 3, farmId: 1, paddockTypeId: 1, harvestYear: 2020, area: 2877 },
    { paddockManagerId: 5, farmId: 2, paddockTypeId: 2, harvestYear: 2017, area: 15902 },
    { paddockManagerId: 3, farmId: 3, paddockTypeId: 2, harvestYear: 2018, area: 1736 },
    { paddockManagerId: 2, farmId: 3, paddockTypeId: 3, harvestYear: 2020, area: 2965 },
    { paddockManagerId: 4, farmId: 3, paddockTypeId: 4, harvestYear: 2018, area: 1651 },
    { paddockManagerId: 5, farmId: 1, paddockTypeId: 1, harvestYear: 2018, area: 700 },
    { paddockManagerId: 1, farmId: 2, paddockTypeId: 1, harvestYear: 2019, area: 7956 },
    { paddockManagerId: 5, farmId: 3, paddockTypeId: 2, harvestYear: 2020, area: 3745 },
    { paddockManagerId: 6, farmId: 1, paddockTypeId: 3, harvestYear: 2021, area: 11362 },
    { paddockManagerId: 2, farmId: 3, paddockTypeId: 3, harvestYear: 2021, area: 300 },
    { paddockManagerId: 3, farmId: 2, paddockTypeId: 2, harvestYear: 2020, area: 19188 },
    { paddockManagerId: 3, farmId: 1, paddockTypeId: 1, harvestYear: 2019, area: 17137 },
    { paddockManagerId: 4, farmId: 3, paddockTypeId: 2, harvestYear: 2020, area: 100 },
    { paddockManagerId: 2, farmId: 1, paddockTypeId: 3, harvestYear: 2019, area: 11845 },
    { paddockManagerId: 5, farmId: 2, paddockTypeId: 1, harvestYear: 2018, area: 15969 },
    { paddockManagerId: 1, farmId: 3, paddockTypeId: 1, harvestYear: 2029, area: 10420 },
    { paddockManagerId: 5, farmId: 2, paddockTypeId: 3, harvestYear: 2010, area: 3200 },
    { paddockManagerId: 6, farmId: 1, paddockTypeId: 2, harvestYear: 2012, area: 10587 },
    { paddockManagerId: 2, farmId: 2, paddockTypeId: 2, harvestYear: 2018, area: 16750 }
  ];

I'm being asked to do the following:

Return an array with the names of each crop, followed by the total sum (area) of each one of them.

As you can see, the second declaration has a paddockTypeId which represents one of the crops in the paddockType array, now I must sum the area of each ID, get the total, and split them based on the crop ID, and also make sure they get correctly paired with their crop names, but as I've said before, I'm lost.

I tried approaching it with a Map, but I just couldn't comprehend the concrete idea of it all. I also checked the documentation, but to no avail.

PD: Also, I'm aware the title may not be very clear, sorry about that!, Any suggestions for a better title will be greatly appreciated!

CodePudding user response：

Here is one attempt using the reduce function

const paddockType = [
    { id: 1, name: 'PALTOS' },
    { id: 2, name: 'AVELLANOS' },
    { id: 3, name: 'CEREZAS' },
    { id: 4, name: 'NOGALES' },
  ]

const paddocks = [
    { paddockManagerId: 6, farmId: 1, paddockTypeId: 1, harvestYear: 2019, area: 1200 },
    { paddockManagerId: 1, farmId: 3, paddockTypeId: 4, harvestYear: 2019, area: 500 },
    { paddockManagerId: 5, farmId: 3, paddockTypeId: 2, harvestYear: 2020, area: 20000 },
    { paddockManagerId: 2, farmId: 2, paddockTypeId: 3, harvestYear: 2021, area: 8401},
    { paddockManagerId: 3, farmId: 1, paddockTypeId: 1, harvestYear: 2020, area: 2877 },
    { paddockManagerId: 5, farmId: 2, paddockTypeId: 2, harvestYear: 2017, area: 15902 },
    { paddockManagerId: 3, farmId: 3, paddockTypeId: 2, harvestYear: 2018, area: 1736 },
    { paddockManagerId: 2, farmId: 3, paddockTypeId: 3, harvestYear: 2020, area: 2965 },
    { paddockManagerId: 4, farmId: 3, paddockTypeId: 4, harvestYear: 2018, area: 1651 },
    { paddockManagerId: 5, farmId: 1, paddockTypeId: 1, harvestYear: 2018, area: 700 },
    { paddockManagerId: 1, farmId: 2, paddockTypeId: 1, harvestYear: 2019, area: 7956 },
    { paddockManagerId: 5, farmId: 3, paddockTypeId: 2, harvestYear: 2020, area: 3745 },
    { paddockManagerId: 6, farmId: 1, paddockTypeId: 3, harvestYear: 2021, area: 11362 },
    { paddockManagerId: 2, farmId: 3, paddockTypeId: 3, harvestYear: 2021, area: 300 },
    { paddockManagerId: 3, farmId: 2, paddockTypeId: 2, harvestYear: 2020, area: 19188 },
    { paddockManagerId: 3, farmId: 1, paddockTypeId: 1, harvestYear: 2019, area: 17137 },
    { paddockManagerId: 4, farmId: 3, paddockTypeId: 2, harvestYear: 2020, area: 100 },
    { paddockManagerId: 2, farmId: 1, paddockTypeId: 3, harvestYear: 2019, area: 11845 },
    { paddockManagerId: 5, farmId: 2, paddockTypeId: 1, harvestYear: 2018, area: 15969 },
    { paddockManagerId: 1, farmId: 3, paddockTypeId: 1, harvestYear: 2029, area: 10420 },
    { paddockManagerId: 5, farmId: 2, paddockTypeId: 3, harvestYear: 2010, area: 3200 },
    { paddockManagerId: 6, farmId: 1, paddockTypeId: 2, harvestYear: 2012, area: 10587 },
    { paddockManagerId: 2, farmId: 2, paddockTypeId: 2, harvestYear: 2018, area: 16750 }
  ];

const result = paddocks.reduce((acc, item) => {
  const name = paddockType.find((e) => e.id == item.paddockTypeId).name;
  acc[name] = (acc[name] ?? 0 )   item.area;
  return acc;
}, {});

console.log(result);

CodePudding user response：

To get the output in an Array format :

const paddockType = [
    { id: 1, name: 'PALTOS' },
    { id: 2, name: 'AVELLANOS' },
    { id: 3, name: 'CEREZAS' },
    { id: 4, name: 'NOGALES' },
  ]

const paddocks = [
    { paddockManagerId: 6, farmId: 1, paddockTypeId: 1, harvestYear: 2019, area: 1200 },
    { paddockManagerId: 1, farmId: 3, paddockTypeId: 4, harvestYear: 2019, area: 500 },
    { paddockManagerId: 5, farmId: 3, paddockTypeId: 2, harvestYear: 2020, area: 20000 },
    { paddockManagerId: 2, farmId: 2, paddockTypeId: 3, harvestYear: 2021, area: 8401},
    { paddockManagerId: 3, farmId: 1, paddockTypeId: 1, harvestYear: 2020, area: 2877 },
    { paddockManagerId: 5, farmId: 2, paddockTypeId: 2, harvestYear: 2017, area: 15902 },
    { paddockManagerId: 3, farmId: 3, paddockTypeId: 2, harvestYear: 2018, area: 1736 },
    { paddockManagerId: 2, farmId: 3, paddockTypeId: 3, harvestYear: 2020, area: 2965 },
    { paddockManagerId: 4, farmId: 3, paddockTypeId: 4, harvestYear: 2018, area: 1651 },
    { paddockManagerId: 5, farmId: 1, paddockTypeId: 1, harvestYear: 2018, area: 700 },
    { paddockManagerId: 1, farmId: 2, paddockTypeId: 1, harvestYear: 2019, area: 7956 },
    { paddockManagerId: 5, farmId: 3, paddockTypeId: 2, harvestYear: 2020, area: 3745 },
    { paddockManagerId: 6, farmId: 1, paddockTypeId: 3, harvestYear: 2021, area: 11362 },
    { paddockManagerId: 2, farmId: 3, paddockTypeId: 3, harvestYear: 2021, area: 300 },
    { paddockManagerId: 3, farmId: 2, paddockTypeId: 2, harvestYear: 2020, area: 19188 },
    { paddockManagerId: 3, farmId: 1, paddockTypeId: 1, harvestYear: 2019, area: 17137 },
    { paddockManagerId: 4, farmId: 3, paddockTypeId: 2, harvestYear: 2020, area: 100 },
    { paddockManagerId: 2, farmId: 1, paddockTypeId: 3, harvestYear: 2019, area: 11845 },
    { paddockManagerId: 5, farmId: 2, paddockTypeId: 1, harvestYear: 2018, area: 15969 },
    { paddockManagerId: 1, farmId: 3, paddockTypeId: 1, harvestYear: 2029, area: 10420 },
    { paddockManagerId: 5, farmId: 2, paddockTypeId: 3, harvestYear: 2010, area: 3200 },
    { paddockManagerId: 6, farmId: 1, paddockTypeId: 2, harvestYear: 2012, area: 10587 },
    { paddockManagerId: 2, farmId: 2, paddockTypeId: 2, harvestYear: 2018, area: 16750 }
  ];

const result = paddockType.map((item) => { 
  const total = paddocks
    .filter((e) => item.id == e.paddockTypeId)
    .reduce((a, e) => a   e.area, 0);
  return { 'name' : item.name, 'total' : total };
});
console.log(result);