基于 Koa平台Node.js开发的KoaHub.js的模板引擎代码

2022-11-07 19:58:54

koahub-handlebars

koahub handlebars templates

Use with koa

var koa = require('koa');

var hbs = require('koahub-handlebars');

var app = koa();

// koahub-handlebars is middleware. `use` it before you want to render a view

app.use(hbs.middleware({

viewPath: __dirname + '/views'

}));

// Render is attached to the koa context. Call `this.render` in your middleware

// to attach rendered html to the koa response body.

app.use(function *() {

yield this.render('index', {title: 'koahub-handlebars'});

})

app.listen(3000);

Registering Helpers

Helpers are registered using the #registerHelper method. Here is an example using the default instance (helper stolen from official Handlebars docs:

hbs = require('koahub-handlebars');

hbs.registerHelper('link', function(text, url) {

text = hbs.Utils.escapeExpression(text);

url = hbs.Utils.escapeExpression(url);

var result = '<a href="' + url + '">' + text + '</a>';

return new hbs.SafeString(result);

});

Your helper is then accessible in all views by using, {{link "Google" "http://google.com"}}

The registerHelper, Utils, and SafeString methods all proxy to an internal Handlebars instance. If passing an alternative instance of Handlebars to the middleware configurator, make sure to do so before registering helpers via the koahub-handlebars proxy of the above functions, or just register your helpers directly via your Handlebars instance.

You can also access the current Koa context in your helper. If you want to have a helper that outputs the current URL, you could write a helper like the following and call it in any template as {{requestURL}}.

hbs.registerHelper('requestURL', function() {

var url = hbs.templateOptions.data.koa.request.url;

return url;

});

Registering Partials

The simple way to register partials is to stick them all in a directory, and pass the partialsPath option when generating the middleware. Say your views are in ./views, and your partials are in ./views/partials. Configuring the middleware via

app.use(hbs.middleware({

viewPath: __dirname + '/views',

partialsPath: __dirname + '/views/partials'

}));

will cause them to be automatically registered. Alternatively, you may register partials one at a time by calling hbs.registerPartial which proxies to the cached handlebars #registerPartial method.

Layouts

Passing defaultLayout with the a layout name will cause all templates to be inserted into the {{{body}}} expression of the layout. This might look like the following.

<!DOCTYPE html>

<html>

<head>

<title>{{title}}</title>

</head>

<body>

{{{body}}}

</body>

</html>

In addition to, or alternatively, you may specify a layout to render a template into. Simply specify {{!< layoutName }} somewhere in your template. koahub-handlebars will load your layout from layoutsPath if defined, or from viewPath otherwise.

At this time, only a single content block ({{{body}}}) is supported.

Options

The plan for koahub-handlebars is to offer identical functionality as koa-hbs (eventaully). These options are supported now.

viewPath: [required] Full path from which to load templates (Array|String)
handlebars: Pass your own instance of handlebars
templateOptions: Hash of handlebars options to pass to template()
extname: Alter the default template extension (default: '.html')
partialsPath: Full path to partials directory (Array|String)
defaultLayout: Name of the default layout
layoutsPath: Full path to layouts directory (String)
disableCache: Disable template caching (default: '.true')

Locals

Application local variables ([this.state](https://github.com/koajs/koa/blob/master/docs/api/context.md#ctxstate)) are provided to all templates rendered within the application.

app.use(function *(next) {

this.state.title = 'My App';

this.state.email = 'me@myapp.com';

yield next;

});

The state object is a JavaScript Object. The properties added to it will be exposed as local variables within your views.

<title>{{title}}</title>

<p>Contact : {{email}}</p>