Routing

Intro

Routing is about associating a component with an URL path.

Define a route

Defining a route is done by associating a URL path with a given component type.

When a page is requested, its URL path is compared with the defined routes. Then a new instance of the component type associated with the route is created and displayed.

Routes are defined by using a simple pattern or by a regular expression.

Simple route

Simple routes are when a component type matches an exact URL path. They are defined with the Route() function:

func main() {
	app.Route("/", &hello{})  // hello component type is associated with default path "/".
	app.Route("/foo", &foo{}) // foo component type is associated with "/foo".
	app.RunWhenOnBrowser()    // Launches the app when in a web browser.
}

Route with regular expression

Routes with regular expressions are when a component type matches an URL path with a given pattern. They are defined with the RouteWithRegexp()function:

func main() {
	app.RouteWithRegexp("^/bar.*", &bar) // bar component is associated with all paths that start with /bar.
	app.RunWhenOnBrowser()               // Launches the app when in a web browser.
}

Regular expressions follow Go standard syntax.

How it works?

Progressive web apps created with the go-app package are working as a single page application. At first navigation, the app is loaded in the browser. Once loaded, each time a page is requested, the navigation event is intercepted and go-app’s routing mechanism reads the URL path, then loads a new instance of the associated component.

routing.png

Detect navigation

Some scenarios may require additional actions to be done when a page is navigated on. Components can detect when a page is navigated on by implementing the Navigator interface:

type foo struct {
    app.Compo
}

func (f *foo) OnNav(ctx app.Context) {
    fmt.Println("component navigated:", u)
}

See component lifecycle.

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