Use for-in instead of Object.keys when serializing
moll opened this issue · 7 comments
Hey,
Object.keys has this peculiar property that it iterates only over own properties. I'd say that's an unnecessary limitations in the serializer given the power of prototypical inheritance.
Interesting. I think its desired b.c I wouldn't want to iterate over the functions of an object, just the properties that are objects themselves. Can you give me an example where Object.keys doesn't work but for-in would?
Unfortunately or not, Object.keys does not skip function properties. For that you always need an explicit typeof test.
As I said, Object.keys does not take inherited properties into account. Inheritance is not at all limited to functions. The following idiom is not that rare and is extremely useful for default properties:
var defaults = {foo: 42, bar: "abc"}
var options = Object.create(defaults)
options.foo = 13When you give that object to logfmt, it'll fail to include bar.
Cheers
@moll - not 100% sure what you're describing is true.
I tried your example:
var defaults = {foo: 42, bar: "abc"}
undefined
var options = Object.create(defaults)
undefined
options.foo = 13
13
var logfmt = require('logfmt')
undefined
logfmt.log(options)
foo=13
undefined
options
{ foo: 13 }
Besides that example, it appears Object.keys works fine with properties added to the object after the fact:
var data = {}
undefined
data.foo = 13
13
logfmt.log(data)
foo=13
Object.keys(data)
[ 'foo' ]
Hey again. Oh, the problem is precisely that bar is not included.
When you for in loop over that object, both foo and bar turn up.