+issue.customfield_12345.map(c => c.value).filter(value => value == "A").length > 0 && issue.customfield_56789 != null

+

+// Priority must have a value and must not have the value Highest

+//You may also want to set the Error message to have text similar to 'You are not permitted to select the Highest Priority'

+

+// Validate that a checkbox custom field contains a specic value  as an option and that a single line text field is not empty

+// Note: You should replace 'customfield_12345' in the example below with the ID of the checkbox field and should replace "A" with the option value to validate against

+// Note: You should replace 'customfield_56789' in the example below with the ID of the single line text field that must not be empty

+

+// Validate that a checkbox custom field only has one value set which is of a specic value and that a single line text field is not empty

+// Note: You should replace 'customfield_12345' in the example below with the ID of the checkbox field and should replace "A" with the option value to validate against

+// Note: You should replace 'customfield_56789' in the example below with the ID of the single line text field that must not be empty

+// Note: You should replace 'customfield_12345' and 'customfield_12346' in the example below with the ID's of the label fields inside of your instance. 

+issue.customfield_12345 !=null || issue.customfield_12346 !=null //You may also want to set the Error message to have text similar to 'You must specify a value in one of the label fields'

+// Validate that a checkbox custom field only has one value set which is of a specic value

+// Note: You should replace 'customfield_12345' in the example below with the ID of the checkbox field and should replace "A" with the option value to validate against

+// Validate that one of two label fields must have a value 

+// Note: You should replace 'customfield_10099' and 'customfield_10100' in the example below with the ID's of the label fields inside of your instance. 

+issue.customfield_10099 !=null || issue.customfield_10100 !=null //You may also want to set the Error message to have text similar to 'You must specify a value in one of the label fields'