Syntax error using => in IE [duplicate]

Question

I have the following line of javascript code

var res = Object.keys(packages).filter(e => packages[e] === true)

The above works well in all the other browser apart from IE. IE complains about Syntax erro at => can someone tell me how to get around this in IE

Answer 1

IE must not support arrow-functions. Just use the old function keyword.

.filter(function(e){ return packages[e] === true })

Side note, but you could also probably write this as:

.filter(function(e){ return packages[e] })

Unless packages[e] must actually be exactly equal to true and not just truthy.