Accessors and mutators in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this accessor?

Given a Laravel model with this accessor, what will $user->full_name output?

class User extends Model {
    public function getFullNameAttribute() {
        return strtoupper($this->first_name . ' ' . $this->last_name);
    }
}

Assuming $user->first_name = 'Jane' and $user->last_name = 'Doe'.

Laravel

class User extends Model {
    public function getFullNameAttribute() {
        return strtoupper($this->first_name . ' ' . $this->last_name);
    }
}

$user = new User();
$user->first_name = 'Jane';
$user->last_name = 'Doe';
echo $user->full_name;

A jane doe

B Jane Doe

C JANE DOE

D Error: Undefined property full_name

💡 Hint

Remember that accessors modify the value when you access the attribute.

The accessor method getFullNameAttribute returns the concatenated first and last name in uppercase. So accessing $user->full_name calls this method and returns 'JANE DOE'.

📝 Syntax

intermediate

Which mutator syntax is correct?

You want to create a mutator in a Laravel model to always store the email attribute in lowercase. Which of these method definitions is correct?

A

public function setEmail($value) {
    $this->attributes['email'] = strtolower($value);
}

B

public function setEmailAttribute($value) {
    $this->attributes['email'] = strtolower($value);
}

C

public function set_email_attribute($value) {
    $this->attributes['email'] = strtolower($value);
}

D

public function setEmailAttribute() {
    $this->attributes['email'] = strtolower($value);
}

💡 Hint

Mutators use camelCase with set + Attribute name + Attribute.

The correct mutator method name is setEmailAttribute and it must accept the $value parameter to modify before saving.

❓ state_output

advanced

What is the value of the attribute after setting it?

Consider this Laravel model mutator:

public function setUsernameAttribute($value) {
    $this->attributes['username'] = trim(strtolower($value));
}

What will be stored in the database if you set $user->username = ' Alice123 ';?

Laravel

public function setUsernameAttribute($value) {
    $this->attributes['username'] = trim(strtolower($value));
}

$user = new User();
$user->username = '  Alice123  ';
echo $user->username;

A Error: Undefined property username

B Alice123

C ALICE123

D alice123

💡 Hint

Mutators change the value before saving it to the attributes array.

The mutator trims whitespace and converts the username to lowercase before storing it. So ' Alice123 ' becomes 'alice123'.

🔧 Debug

advanced

Why does this accessor not work?

This Laravel model accessor is supposed to return the user's age, but it causes an error:

public function getAgeAttribute() {
    return $this->birthdate->diffInYears(now());
}

Assuming birthdate is a date string stored in the database, why does this cause an error?

A birthdate is a string, not a Carbon date object, so diffInYears method is undefined

B The birthdate attribute is private and cannot be accessed

C The now() function is not imported and causes a fatal error

D The accessor method name is incorrect; it should be get_age_attribute

💡 Hint

Check the data type of birthdate when accessed in the model.

Laravel does not automatically convert date strings to Carbon objects unless the attribute is cast as a date. Without casting, birthdate is a string and calling diffInYears on it causes an error.

🧠 Conceptual

expert

How do accessors and mutators affect JSON serialization?

In Laravel, when you convert a model to JSON using toJson(), which of the following statements about accessors and mutators is true?

A Accessors are applied and their values appear in the JSON, but mutators do not affect JSON output

B Mutators modify the JSON output values, but accessors do not

C Neither accessors nor mutators affect the JSON output; only raw attributes are shown

D Both accessors and mutators modify the JSON output values

💡 Hint

Think about when accessors and mutators run in the model lifecycle.

Accessors modify attribute values when reading, so their computed values appear in JSON. Mutators modify values only when setting attributes, so they do not affect JSON output directly.