Sum of hour nestjs

Question

In the javascript code below in the function execute a select on a db (using typerom) from which an array formatted as follows:

JSON Data Example:

{
        "id": 1,
        "nome": "prova2",
        "datacreazione": "2021-09-05T08:41:29.000Z",
        "costo": 23,
        "ore": "08:00",
        "IdPreventivo": 1,
        "IdUtente": 2
    },
    {
        "id": 2,
        "nome": "prova2",
        "datacreazione": "2021-09-06T08:38:26.000Z",
        "costo": 23,
        "ore": "08:00",
        "IdPreventivo": 1,
        "IdUtente": 2
    }

the hours (ore) field contains the total hours of the activity carried out what I want to do is calculate the total hours by adding and exegundo a sum of all the ore entered in that field for each element of the array, the hours they are in the format HH: MM, how can I go about doing this?

AttivitaprevService.js

@Injectable()
export class AttivitaprevService {
  constructor(
    @InjectRepository(Attivitaprev) private repo: Repository<Attivitaprev>
  ) {}

  create(dto: CreateAttivitaprevDto) {
    return this.repo.save(dto);
  }

  findAll() {
    return `This action returns all attivitaprev`;
  }

  async findOne(id: number) {
    return await this.repo.find({
      where: { IdPreventivo: id },
    });
  }

  sumofhour = (time1, time2) => {
    let [h1, m1] = time1.split(':')
    let [h2, m2] = time2.split(':')
  
    return ((+h1 + (+m1 / 60)) + (+h2 + (+m2 / 60)))
  }

  async totaleore(id: number) {
    var values= await this.repo.find({
      where: { IdPreventivo: id },
    });

    return values;
  }

..

Answer 1

Please see the Array.reduce implementation.

const data = [
  {
    "id": 1,
    "nome": "prova2",
    "datacreazione": "2021-09-05T08:41:29.000Z",
    "costo": 23,
    "ore": "08:30",
    "IdPreventivo": 1,
    "IdUtente": 2
  },
  {
    "id": 2,
    "nome": "prova2",
    "datacreazione": "2021-09-06T08:38:26.000Z",
    "costo": 23,
    "ore": "08:30",
    "IdPreventivo": 1,
    "IdUtente": 2
  }
]
sumofhour = () => {
  const sum = data.reduce((acc, curr) => {
    let [h1, m1] = curr.ore.split(':');
    acc += (+h1 + (+m1 / 60));
    return acc;
  }, 0)
  return sum;
};
console.log(sumofhour());