Simple email mailer

Mailer.php

<?php

// $mailer = new Mailer(Obj). Obj is expected to be a parsed JSON object from the front end
// Example {"email": "person@mailing.com", "name": "Person Mailing", "message": "Hello"}
// you decode_json(Obj, true); first before instantiating the mail object with it.
// Mailer will echo a JSON string of either a success message or an array of errors after attempting
// to sanitize, validate and send mail. use $mailer->send(); to run the module after instantiating it.

class Mailer {
  function __construct($envelope) {
    // Fill out whom this is going to
    $this->recipient = 'mailto@email.com';
    $this->headers = 'From: website.com <mailer@website.com>';

    //Constructed automagically
    $this->name = $envelope['name'];
    $this->email = $envelope['email'];
    $this->message = $envelope['message'];
    $this->errors = Array();
  }

  function sanitize() {
    $newLines = '/\\\\r|\\\\n/i';
    $this->name = preg_replace($newLines, "", $this->name);
    $this->email = preg_replace($newLines, "", $this->email);
    $testString = $this->name.$this->email;
    $injection = "/(bcc:|cc:|content\-type:)/i";
    if (preg_match($injection, $testString)){
      array_push($this->errors, (object)['critical'=> 'Header Injection']);
    }
  }

  function validate(){
    $this->sanitize();

    $fields = array(
      "name" => $this->name,
      "email" => $this->email,
      "message" => $this->message
    );

    foreach($fields as $key => $value){
      switch ($key){
        case 'email':
          if ($value && filter_var($value, FILTER_VALIDATE_EMAIL) === false){
            array_push($this->errors, (object)['email' => $value.' isn\'t a valid email']);
          }
        default:
          if(!$value) {
            array_push($this->errors, (object)[$key => 'please provide your '.$key]);
          }
      }
    }
  }

  function sendMail() {
    $subject = $this->name." sent you a message!";
    $body = "You received a new message from ".$this->name." (".$this->email.") from justineshu.com! 

Message:

".$this->message;
    if (mail($this->recipient, $subject, $body, $this->headers)) {
      echo json_encode((object)["success" => "Sent"], JSON_UNESCAPED_SLASHES);
    } else {
      array_push($this->errors, (object)["mailer" => "There was a problem sending the message.  Please try again or email info@justineshu.com directly"]);
      echo json_encode((object)["errors" => $this->errors], JSON_UNESCAPED_SLASHES);
    }
    
  }

  function send() {
    $this->validate();
    if ($this->errors) {
      echo json_encode((object)["errors"=> $this->errors], JSON_UNESCAPED_SLASHES);
    } else {
      $this->sendMail();
    }
  }

}

?>