new to ng4/typescript and having some difficulty. How do I sum the items in an array?

Added screenshot of what it looks like in action for example

        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)

             }
          }

new to ng4/typescript and having some difficulty. How do I sum the items in an array?

Added screenshot of what it looks like in action for example

        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)

             }
          }

• javascript
• arrays

• 1 Start by a simpler task. Try summing the elements of the following array: [1, 2, 3, 4]. – JB Nizet Commented Nov 4, 2017 at 17:09
• Possible duplicate of How to find the sum of an array of numbers – edkeveked Commented Nov 4, 2017 at 17:15

2 Answers 2

Use 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);

let sum = array.reduce(function (acc, cur) { return acc + cur; });