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Comment by oldmanjay | Hacker News Reader

You call it beautiful, but that's a fair stretch. It's more compact than JavaScript but to non-Ruby eyes, there's no real beauty to be found. It's just simple substitutions that otherwise look the same.

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A key difference in Ruby is that while blocks are conceptually just another argument, they aren't part of the syntactical argument list. This:

  strings.map { |s| s.upcase }

is actually:

  strings.map() { |s| s.upcase }

...and this is what it's not:

  strings.map({ |s| s.upcase })  # Invalid

It's subtle, but it does make for a simpler, more readable syntax that lends itself to DSLs, since no parantheses are needed:

  validate :name { |name|
    errors.add("Bad name") unless name
  }

It's feasible in other languages, of course; Elixir, for example, introduces a Ruby-like "do" block syntax which is more regular than Ruby's. It might be too late for JavaScript, but I'm no parser expert.

They're simple examples that fit into one line. The difference is more notable on longer chains. I think people currently avoid this block style[1] syntax in JS because it's verbose. Arrow functions fix that.

[1] Again, not sure of the correct term for this - functional style?

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