Else statement

[lobre]

Hi,

In html/template, you can use if/else instructions. In gomponents, only .If is supported.

Here is an example.

{{if .IsAuthenticated}}
  Hello {{.Username}}!
{{else}}
  Please log in.
{{end}}

How would to handle such a situation with gomponents? Could a .If(...).Else(...) be useful?

Same but different, how would you handle a loop on a range?

Thanks

[markuswustenberg]

Basically, negate the conditional expression:

func component(condition bool) g.Node {
  return Div(
    g.If(condition, …),
    g.If(!condition, …),
  )
}

Instead of looping, use Map. Or is there something you need that you don't get from looping?

[markuswustenberg]

By the way, you can always do something like this if you want imperative code inline:

func component(numbers []int) g.Node {
  return Div(
    func() g.Node {
      for _, n := range numbers {
        …
      }
      return someOtherComponent(…)
    }()
  )
}

[lobre]

Great examples, thanks for providing those. They answer my concerns!

[wworrall]

Thank you @markuswustenberg for providing a simple solution to this. I came across this in a search for If/Else functionality too. I often find myself writing:

g.If(condition, ...)
g.If(!condition, ...)

Whilst we could all add a simply utility function to our projects, I wonder whether it is such a common need that it might be worth adding to gomponents?

A possible function signature:

g.IfElse(
   condition,
   trueComponent(),
   falseComponent(),
)

Happy to contribute but unsure whether this aligns with the ethos of the lib? I, personally, find myself wanting this in gomponents.

[markuswustenberg]

I actually really like the simplicity of just having If, but I acknowledge that it comes down to code style. Personally, I almost never use else anywhere unless it's really the most obvious solution.

So I'm leaning towards not adding it. I favor having a smaller API vs. the arguably small added convenience of not having to negate the conditional expression.

[wworrall]

Sure, I appreciate this! And on consideration, if the lib were to support if/else, then it would lead to if/else if/else support which perhaps would require chaining. And the complexity grows.