When using JavaScript's reduce, how do I skip an iteration?

Question

I am trying to figure out a way to conditionally break out of an iteration when using JavaScript's reduce function.

Given the following code sums an array of integers and will return the number 10:

[0, 1, 2, 3, 4].reduce(function(previousValue, currentValue, currentIndex, array) {   return previousValue + currentValue; }); 

How can I do something like this:

[0, 1, 2, 3, 4].reduce(function(previousValue, currentValue, currentIndex, array) {   if(currentValue === "WHATEVER") {     // SKIP or NEXT -- don't include it in the sum   }   return previousValue + currentValue; }); 

Answer 1

You can just return previousValue

[0, 1, 2, 3, 4].reduce(function(previousValue, currentValue, currentIndex, array) {   if(currentValue === "WHATEVER") {     return previousValue;   }   return previousValue + currentValue; }); 

Answer 2

You can simply use a ternary operator to pass the previous value if the condition is true ..or perform a certain action if false

[0, 1, 2, 3, 4].reduce((previousValue, currentValue, currentIndex, array)=>  {   return(condition)?  previousValue : previousValue + currentValue; });