How do I chain methods in PHP?

Method chaining in PHP allows you to call multiple methods on an object in a single line by returning $this from each method. This creates a fluent interface that makes code more readable and concise.

How Method Chaining Works

To enable method chaining, each method must return the current object instance using return $this. This allows the next method to be called on the returned object ?

<?php
class sample_class {
    private $str;
    
    function __construct() {
        $this->str = "";
    }
    
    function addA() {
        $this->str .= "am";
        return $this;
    }
    
    function addB() {
        $this->str .= "_bn";
        return $this;
    }
    
    function getStr() {
        return $this->str;
    }
}

$new_object = new sample_class();
echo $new_object->addA()->addB()->getStr();
?>

am_bn

Practical Example

Here's a more practical example with a QueryBuilder class ?

<?php
class QueryBuilder {
    private $query = "";
    
    public function select($fields) {
        $this->query = "SELECT " . $fields;
        return $this;
    }
    
    public function from($table) {
        $this->query .= " FROM " . $table;
        return $this;
    }
    
    public function where($condition) {
        $this->query .= " WHERE " . $condition;
        return $this;
    }
    
    public function getQuery() {
        return $this->query;
    }
}

$builder = new QueryBuilder();
$sql = $builder->select("name, email")
              ->from("users")
              ->where("age > 18")
              ->getQuery();

echo $sql;
?>

SELECT name, email FROM users WHERE age > 18

Key Points

• Always return $this from methods you want to chain
• The last method in the chain can return any value (not necessarily $this)
• Method chaining improves code readability and reduces variable assignments
• Commonly used in frameworks like Laravel for query building and form handling

Conclusion

Method chaining in PHP creates fluent interfaces by returning $this from each method. This pattern makes code more readable and allows for elegant, chainable API designs commonly seen in modern PHP frameworks.