What's the preferred way to dump a JSON object? to_json, JSON.generate or JSON.dump?

Question

I need to dump a hash object to JSON and I was wondering which of these three, to_json, JSON.generate or JSON.dump, is the preferred way to do it.

I've tested the results of these methods and they are the same:

> {a: 1, b: 2}.to_json
=> "{\"a\":1,\"b\":2}" 
> JSON.generate({a: 1, b: 2})
=> "{\"a\":1,\"b\":2}" 
> JSON.dump({a: 1, b: 2})
=> "{\"a\":1,\"b\":2}"

Answer 1

For dumping arrays, hashs and objects (converted by to_hash), these 3 ways are equivalent.

But JSON.generate or JSON.dump only allowed arrays, hashs and objects.

to_json accepts many Ruby classes even though it acts only as a method for serialization, like a integer:

JSON.generate 1 # would be allowed
1.to_json # => "1"

JSON.generate took more options for output style (like space, indent)

And JSON.dump, output default style, but took a IO-like object as second argument to write, third argument as limit number of nested arrays or objects.