Day 31 changing to day 1 in typescript-CodePudding

When a put day 31 in the input field, the JSON 'dt_ini_vigencia' and 'dt_fin_vigencia' is changing for day 1. could anyone help me understand this?

JSON date format in input: '2022-12-31T03:00:00.000Z' this is what the JSON returns after this function: '2022-12-01T03:00:00.000Z' to 'dt_ini_vigencia' '2023-12-01T03:00:00.000Z' to 'dt_fin_vigencia'.

this problem only happens when a put day 31 in the input

var cotacaoJson = JSON.parse(resp[0].ds_cotacao_json);
          var date = new Date();
          date.setDate(cotacaoJson.dt_ini_vigencia.substring(8, 10)); //apparently is on this line
          date.setMonth(cotacaoJson.dt_ini_vigencia.substring(5, 7) - 1);
          date.setFullYear(cotacaoJson.dt_ini_vigencia.substring(0, 4));
          date.setHours(0);
          date.setMinutes(0);
          date.setSeconds(0);
          date.setMilliseconds(0);

          var dateF = new Date();
          dateF.setDate(cotacaoJson.dt_fin_vigencia.substring(8, 10));
          dateF.setMonth(cotacaoJson.dt_fin_vigencia.substring(5, 7) - 1);
          dateF.setFullYear(cotacaoJson.dt_fin_vigencia.substring(0, 4));
          dateF.setHours(0);
          dateF.setMinutes(0);
          dateF.setSeconds(0);
          dateF.setMilliseconds(0);

          this.cotacao = cotacaoJson;

          if (!this.editar)
          {
            this.cotacao.clausulas_particulares = 'N/A';
          }

          this.cotacao.dt_ini_vigencia = date;
          this.cotacao.dt_fin_vigencia = dateF;

save the 31st in date and dateF

CodePudding user response：

It is because new Date() returns the current date. It is November now, so the maximum date you can pass is 30. To fix this first set year, then a month, and only then a date

CodePudding user response：

Just use some robust and well tested library function for date parsing like parseJSON from date-fns rather than re-inventing the wheel.