Array_ 01return in foreach

return keyword

return Keyword Introduction

break And continue keyword

break And continue Keyword Introduction

forEach Medium return

• [1]forEach The function is to cycle the array , But the essence is a function , therefore stay forEach It can't be used directly break And continue To stop the cycle ( Will report a mistake );

• [2] that forEach How to terminate the loop ？

  • forEach The essence is a function , Use return You can terminate the execution of the function ;
  • Encapsulate inside the function
    • return true amount to continue; End this cycle , Execute next cycle ;
    • return false amount to break ; End of cycle , Execute the statement after the loop ;

• [3] If used inside a function forEach

  •       function getNum(arr){
            
              let sum = 0
              arr.forEach(item=>{
            
                sum +=item
                if(item == 5){
            
                    return sum
                }
              })
              return sum
            }
            const sum = getNum([1,3,5,7,9])
            console.log(' result ',sum) // 25
    

    • stay item == 5 when ,sum by 9 Convert to boolean When the value is 0 true; —> stay forEach Inside return true It will be resolved to continue( Jump out of this cycle and execute the next cycle );
      - So you can see that if you want to use loops inside functions and inside loops return Words , Out of commission forEach For loop traversal ！