Convert Javascript Array of Strings to Comma Separated - gecko-8/devwiki GitHub Wiki
Use the Javascript array .join(separator) method
const result = myarray.join(',')
NOTE: The separator can be any string. E.g. .join(', ') will separate with a comma followed by a space.
If you have an array of objects and you want a comma (or any separator) separated string of one of the properties, do a map first.
const result = myarray.map(item => item.name).join(',');