Uncaught Typeerror: Cannot Read Property 'keys' Of Undefined

I have these data in my console. var uniqVisitorDeviceType = visitorDeviceType.reduce((acc, val) => { acc[val] = acc[val] === undefined ? 1 : acc[val] += 1; return acc; },

Solution 1:

You have an Object, not an array. Use Object.keys(uniqVisitorDeviceType) instead.