Code Snippet: Error Check for Open/Unsaved Doc

Error Check for Open or Unsaved Doc.jsx

if (!documents.length) {
   alert('There are no documents open.', 'No Document');

} else {
   alert('You have a document open!');
}

// or

if (app.documents.length > 0) {
    alert('You have a document open!');

} else {
    alert('You must have a document open!');
}
    
// or

if (app.documents.length != 0) {
    alert('You have a document open!');

} else {
    alert('You must have a document open!');
}

// or

/* Start Open/Saved Document Error Check - Part A: Try */
savedDoc();
function savedDoc() {
  try {
    app.activeDocument.path;
/* Finish Open/Saved Document Error Check - Part A: Try */

/* Main Code Start */
    alert("Replace this alert with your main code");
/* Main Code Finish */
}

/* Start Open/Saved Document Error Check - Part B: Catch */
  catch (err) {
    alert("An image must be open and saved before running this script!");
  }
}
/* Finish Open/Saved Document Error Check - Part B: Catch */