Why Does My Function Return `undefined` When Using `forEach`?

Function Fails to Return Value When Utilizing forEach Method

Upon creating a function to inspect object array values, it unexpectedly returns undefined. This issue has sparked confusion, and we will delve into the reasons behind this behavior.

Problem Explanation

In the provided code snippet, the getByKey function employs the forEach method to traverse the data array. Inside the callback function, you attempt to return a value based on a conditional check. However, this return statement only exits the anonymous function passed to forEach, not the getByKey function itself. As a result, undefined is returned from the getByKey function call.

Solutions

There are several ways to resolve this issue:

1. Use a For Loop: Replace forEach with a traditional for loop. This approach allows you to return the desired value from the loop itself.

   function getByKey(key) {    
       for (var i = 0; i < data.length; i++) {
           if (data[i].Key === key) {
              return data[i];
           }
       }
   }

2. Store the Result in a Variable: In the callback function, assign the matched value to a variable and return that variable from the getByKey function.

   function getByKey(key) {    
       var found = null;
       data.forEach(function (val) {
           if (val.Key === key) {
               found = val;
           }
       });
       return found;
   }

By implementing these solutions, you ensure that the getByKey function properly returns the desired value when a match is found.

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