Code Smell 72 - Return Codes

Don't return codes to yourself. Raise Exceptions.

24 May, 2023

Contributors

Maxi Contieri

@mcsee

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Outdated documentation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