Me gustaría sumar las ventas totales por CPF, logré separar el CPF pero borré cómo hacer la suma ahora, vea mi código a continuación
var vendas = [{cpf: "14382435021", amount: 34.5 }, { cpf: "79785337006", amount: 12 }, { cpf: "79785337006", amount: 23.16 }, { cpf: "14382435021", amount: 46.4 }, { cpf: "88835414059", amount: 26.2 }, { cpf: "88835414059", amount: 199.9 }, { cpf: "79785337006", amount: 18.16 } ] var resultados = {}; for(var i = 0; i < vendas.length; i++){ if(vendas[i].cpf){ if(!resultados[vendas[i].cpf]){ resultados[vendas[i].cpf] = [] } resultados[vendas[i].cpf].push(vendas[i]); } } console.log(resultados)<script> var vendas = [{cpf: "14382435021", amount: 34.5 }, { cpf: "79785337006", amount: 12 }, { cpf: "79785337006", amount: 23.16 }, { cpf: "14382435021", amount: 46.4 }, { cpf: "88835414059", amount: 26.2 }, { cpf: "88835414059", amount: 199.9 }, { cpf: "79785337006", amount: 18.16 } ] var result = []; vendas.reduce(function(res, value) { if (!res[value.cpf]) { res[value.cpf] = { cpf: value.cpf, amount: 0 }; result.push(res[value.cpf]) } res[value.cpf].amount += value.amount; return res; }, {}); console.log(result) </script>