Multiple conditional emails sent based on Google Form submission - email

Question

I use the below script with a google form which sends an email to different people based on the answer chosen on the form. The script works and sends an email to the correct person when I use it with a form where the user can only choose one option.
But now I have a form where a user can choose between 1 and 6 options for the selection of cases to match. For every option chosen, I need an email to be sent to the corresponding department. With switch command, I understand that it tests an expression against a list of cases and returns the corresponding value of the first matching case. What I need is for it to test against a list of cases and return ALL corresponding values and then email based on that. Sometimes that would be one email, sometimes that could be 3 emails to 3 different people, etc.
The question on the google form is a checkbox question so a user can choose any and all if it applies. Each option correlates with a different email in my script.
Currently, if the form is filled out and only one option is chosen (see screenshot question "announcement outlet"), the script runs and sends the email as it should. But if two or more options are selected, no email goes out. When I check the trigger notes, the error is:
Exception: Failed to send email: no recipient
at sendFormByEmail(Code:47:13)
Here is my current script which works when only one option can be chosen. I believe I need a different command other than switch, but don't know what. I looked into fallthrough, but don't think that would work for this either.
function sendFormByEmail(e)
{      
// Remember to replace XYZ with your own email address  
var named_values = e.namedValues  
var teachername = named_values["Teacher Name"];    
var info = named_values["Your message/announcement"];  
var time = named_values["Please include time frame"];  
var photos = named_values["Include photos with this form if applicable; you can also create the graphic for social media and include below"];  
var announce = named_values["Choose announcement outlet"].toString();  
var email;
 
 // Optional but change the following variable  
// to have a custom subject for Google Docs emails  
  
// The variable e holds all the form values in an array.  
// Loop through the array and append values to the body.  
var message = "";      
for(var field in e.namedValues) {    
message += field + ' :: ' 
              + e.namedValues[field].toString() + "\n\n"; 
 }   
  switch (announce) {    
case "School Intercom Announcement":      
var email = "person1#school.net";      
break;    
case "MHHS Website":      
var email = "person2#school.net";      
break;    
case "MHHS Social Media (Instagram, Facebook, Twitter)":      
var email = "person3#school.net"     
break;    
case "Week in Pics":      
var email = "person4#school.net"  
var body = "Week in Pics Request"    
break;  
case "Remind text message (goes to students - please specify in your message info if it is all grades or specific grades)":
var email = "person5#school.net"
var subject = "Remind Text Request"
break;
case "Phone call home":
var email = "person6#school.net"
break;
}  
 // This is the MailApp service of Google Apps Script  
// that sends the email. You can also use GmailApp here.  
MailApp.sendEmail(email, subject, message);   
}
When multiple options are chosen, the data in the cell reads "Option 2, Option 4" and all my listed cases in the script above are for only "Option 2" or "Option 4", etc. Is there a way make this happen without having to make a case for every possible combination of the 6 choices that could potentially happen?

Answer 1

One way to fix the code
Remove .toString() from var announce = named_values["Choose announcement outlet"].toString();. Rationale: There is no need to convert an Array into a string for this case.
Instead of switch use if's, more specifically, add one if for each case clause, using an expression to test if the case label is included in announce. Example:
Replace
case "School Intercom Announcement":
by
if(announce.includes("School Intercom Announcement")){
// put here the case clause, don't include break;
// Add the following line before the closing `}` of the if statement
MailApp.sendEmail(email, subject, message);
}
Rationale: It's easier to implement the required control logic using if and Array.prototype.includes rather than doing it using switch.