Angular 4 - 数组之和

Question

ng4/typescript 的新手并且有一些困难。如何对数组中的项目求和？

添加 例如，它在行动中的样子的屏幕截图

        for (let card of this.cards) {
              for (let val of card.cards){
                if(val.value == "JACK"){
                  val.value = 10;
                }
                if (val.value == "QUEEN"){
                  val.value = 10;
                }
                if (val.value == "KING"){
                  val.value = 10;
                }
                if (val.value == "ACE"){
                  val.value = 10;
                }

                this.hand = Number(val.value) + Number(val.value); (I'm sure this is wrong)

             }
          }

Answer 1

使用Array#Reduce：

// Array of numbers
var array = [1,2,3,4,5];
var sum = array.reduce((acc, cur) => acc + cur, 0);
console.log(sum)

// Array of strings
var toNumber = ['1','2','3','4','5'];
var sumNumber = toNumber.reduce((acc, cur) => acc + Number(cur), 0)
console.log(sumNumber);