Well for one you're missing a closing } in that function. But you could just do const showTable = ["email", "phone","website"] .reduce((previous, channel

Well for one you're missing a closing } in that function. But you could just do const showTable = ["email", "phone","website"] .reduce((previous, channel) => { return previous || !!institution[channel] && !/^\s*$/.test(institution[channel]) }), false) You can always just replace function() { with () => { and the only difference between the two would be binding this. Or you could do this: const showsTable = ["email", "phone", "website"] .reduce((previous, channel) => previous || !!institution[channel] && !/^\s*$/.test(institution[channel]), false)