Setting children from go code #909

rotemhoresh · 2024-09-07T20:24:35Z

The title basically, e.g.:

// comp.templ
templ Comp() {
    <div class="error">
        { children... }
    </div>
}

// render.go
Comp().Render(ctx, w)  // how to set children components / raw HTML from here?

a-h · 2024-09-08T09:10:53Z

To pass children in code, you can use the templ.WithChildren function to create a context that has children:

ctx := templ.WithChildren(ctx, child)
err := Comp().Render(ctx, sb)

The inverse (getting the children from within Go code) is done with the templ.GetChildren function.

templ/runtime.go

Lines 60 to 82 in e2511cd

    
           func WithChildren(ctx context.Context, children Component) context.Context { 
        
           	ctx, v := getContext(ctx) 
        
           	v.children = &children 
        
           	return ctx 
        
           } 
        
           func ClearChildren(ctx context.Context) context.Context { 
        
           	_, v := getContext(ctx) 
        
           	v.children = nil 
        
           	return ctx 
        
           } 
        
           // NopComponent is a component that doesn't render anything. 
        
           var NopComponent = ComponentFunc(func(ctx context.Context, w io.Writer) error { return nil }) 
        
           // GetChildren from the context. 
        
           func GetChildren(ctx context.Context) Component { 
        
           	_, v := getContext(ctx) 
        
           	if v.children == nil { 
        
           		return NopComponent 
        
           	} 
        
           	return *v.children 
        
           }

There can only actually be one child. We haven't (currently) got an API to concatenate multiple templ components into a single component. The consensus is that adding templ.Join to do that would be useful, as per #788

That way, you could have templ.WithChildren(ctx, templ.Join(childA, childB, childC)) although, we'd probably update templ.WithChildren to take a variadic param, so you could do templ.WithChildren(ctx, childA, childB, childC) and do the templ.Join inside the function call.

a-h · 2024-09-08T09:28:39Z

I've updated the docs to include this information. Feel free to re-open etc. if needed.

linear bot added question Further information is requested docs labels Sep 8, 2024

a-h closed this as completed in 5044001 Sep 8, 2024

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