APIs, Return codes, C Programming Language, We've all been there.

TL;DR: Don't return codes to yourself. Raise Exceptions.

Problems

IFs
Code Polluting
Outdated documentation
Coupling to accidental codes.
Functional logic polluted.

Solutions

Change Ids and return Generic Exceptions.
Distinguish Happy Path from Exception Path.

Sample Code

Wrong

function createSomething(arguments) {
    //Magic Creation
    success = false; //we failed

    //We failed to create
    if (!success) {
        return {
            object: null,
            errorCode: 403,
            errorDescription: 'We didnt have permission to create...'
        };
    }

    return {
        object: createdObject,
        errorCode: 400,
        errorDescription: ''
    };
}

var myObject = createSomething('argument');
if (myObject.errorCode != 400) {
    console.log(myObject.errorCode + ' ' + myObject.errorDescription)
}
//but myObject does not hold My Object but an implementative
//and accidental array 
//from now on me need to remember this

Right

function createSomething(arguments) {
    //Magic Creation
    success = false; //we failed

    //We failed to create
    if (!success) {
        throw new Error('We didnt have permission to create...');
    }

    return createdObject;
}

try {
    var myObject = createSomething('argument');
    //no IFS, just happy path
} catch (exception) {
    //deal with it!
    console.log(exception.message);
}
// myObject holds my expected object

Detection

We can teach our linters to find patterns of integer and strings returns coupled with ifs and return checking.

Conclusion

Ids and codes are external identifiers.

They are useful when you need to interact with an external system (for example an API Rest).

We should not use them on our own systems and our own internal APIs.

Create and raise generic exceptions.

Only create specific exceptions if you are ready to handle them, and they have specialized behavior.

Don't create anemic Exceptions.

Avoid immature and premature optimized languages favoring return codes.

Relations

Code Smell 26 - Exceptions Polluting

Maxi Contieri ・ Nov 16 '20

#oop #exceptions #tutorial #programming

More info

How to Get Rid of Annoying IFs Forever

Maxi Contieri ・ Nov 9 '20

#oop #programming #codenewbie #tutorial

Clean code

Credits

Photo by Alex Hay on Unsplash

Error handling is important, but if it obscures logic, it’s wrong.

Robert Martin

Software Engineering Great Quotes

Maxi Contieri ・ Dec 28 '20

#codenewbie #programming #quotes #software

This article is part of the CodeSmell Series.

How to Find the Stinky parts of your Code

Maxi Contieri ・ May 21 '21

#codenewbie #tutorial #codequality #beginners

Code Smell 72 - Return Codes