I am trying to use LFForm.changeActionButton to change the text of the submission button based on the result of a look up. I get this Uncaught TypeError listed in the title when I load the page. 

Here is my code: 

 

LFForm.onLookupDone(function () {
    let parentID = LFForm.getFieldValues({fieldId: 5});
    
    if (parentID == 422624) {
    	LFForm.changeActionButton("Submit", {label: "Close"});
    } else if (parentID == 4229023) {
    	LFForm.changeActionButton("Submit", {label: "Open"});    
    } else {
     	LFForm.changeActionButton("Submit", {label: "No Case Found"}); 
    }
}, {lookupRuleId: 1});

Any suggestions? I copied the code from  Business Processes > Creating a New Form > CSS and JavaScript in the Forms Designer > The LFForm Object document