I'm passing a variable to my template renderer in ExpressJs like so:
index.js
app.get('/simple_view/', function(req, res, next){
title='A TITLE';
res.render('simple', {
title: title
});
});
I would like to access the title variable in a JS script on my template page, but I'm getting Uncaught ReferenceError: title is not defined error.
simple.pug
script.
console.log(title);
How can I solve this?
The Getting Started for PUG already showcases how to embed variables. You do this by using #{variable_name}, e.g. #{title} in your case.
I used NodeJs with Handlebars and thought about switching to PugJs because some functionality is native - using Handlebars requires some helper functions / partials.
In Handlebars I have to define a layout and pass in the template. In PugJs I created two example routes
First route file:
const express = require('express');
const router = express.Router();
router.get('/', (req, res) => {
res.render('index', {
title: 'Home',
template: 'main'
});
});
module.exports = router;
Second route file:
const express = require('express');
const router = express.Router();
router.get('/', (req, res) => {
res.render('index', {
title: 'Page2',
template: 'pageTwo'
});
});
module.exports = router;
As you can see I always have to render my index file and pass in the desired pug file as a template variable.
index.pug
doctype html
html
include ./header.pug
body
include ./templates/#{template}.pug
header.pug
head
title #{title} template!
main.pug
script(src='./client/main.js')
h1 main content here
pageTwo.pug
p pageTwo
When rendering the pug files I get this error
ENOENT: no such file or directory, open
'...\views\templates\#{template}.pug'
How can I replace #{template} with the correct template variable?
Dynamic template selection isn't a feature of pug, I believe it has something to do with how pug pre-compiles everything into a JavaScript function that stays in-memory inside node.js when it runs. The benefit of that is super-fast page rendering, so we're happy to keep using pug and just work around this.
Speaking of which, you can accomplish what you want to do using conditional logic:
doctype html
html
include ./header.pug
body
if template === 'pageOne'
include ./templates/pageOne.pug
else if template === 'pageTwo'
include ./templates/pageTwo.pug
else
include ./templates/home.pug
You should also look into the extends feature to simplify adding the header into your templates and mixins to resuse code between templates. You might find that these features could provide a better solution to your requirements with some redesign.
I'm rendering my pages with pugJS like this:
res.render('test',renderVars)
This render uses a layout, in which I need to get the 'test' string. My question is: how can I get the 'test' string so that I can use it in my layout? I could put a new variable in 'renderVars' but I'm sure there is a better solution.
In other words: how can I get the name of a template inside this template? Something like #{templatename} for example?
Thanks in advance!
I'm afraid you can't do so. res.render 1st parameter is rendering a view template not mean to store data. You could set the 'test' in renderVars or you can add it in session and will be able to use it in your layout.
Add this code into your app.js before the routes and after session settings
//inject session into res.locals so can be rendered in UI
app.use(function (req, res, next) {
if (req.session.message) {
res.locals.message = req.session.message;
delete req.session.message;
}
res.locals.session = req.session;
next();
});
In the view template you can access the res.locals.session data by using
#{session.theAttributeYouWant)
I'd like to set my CSS path in my express application in order to use this one in my jade layouts. However, I don't know how to do, I try to use "app.set('cssPath', __dirname+'/public/admin/css/')" but it doesn't work because I can not use "app.get()" in my external controllers.
My layout _layout.jade :
!!! 5
html(lang='fr')
head
meta(charset='UTF-8')
link(href='admin/css/screen.css', media='screen, projection', rel='stylesheet', type='text/css')
body
.container
h1 Wellcome to Forest Administrator
.space20
block content
.clear.space20
script(type='text/javascript', src='admin/js/jquery.js')
My page edit.jade :
extends ../_layout
block content
.block.half.first
h2 Add a post
And I'd like to use something like :
link(href='+myCssPath+', media='screen, projection', rel='stylesheet', type='text/css')
Not sure if I get what you want to do but You can use
res.locals.cssPath = 'string with the path';
And cssPath will be available in your template.
Besides that you don't need __dirname+'/public/. Part because when the page is rendered for the browser /public/ will be /
[edit] If you want to have that variable available in all you routes, but declaring it just once, you can create a small middleware like
var express = require('express');
var app = express();
var app.configure(function(){
app.use(express.bodyParser());
app.use(express.methodOverride());
// .. and your other tipical configuration
//this small middleware for variables that must available in all paths
app.use(function(req, res, next) {
res.locals.cssPath = 'path to the css directory';
next();
});
});
//From here your typical route declarations
app.get('/', function(req, res) { res.render('someView'); });
Ok, so I have built a blog using Jekyll and you can define variables in a file _config.yml which are accessible in all of the templates/layouts. I am currently using Node.JS / Express with EJS templates and ejs-locals (for partials/layouts. I am looking to do something similar to the global variables like site.title that are found in _config.yml if anyone is familiar with Jekyll. I have variables like the site's title, (rather than page title), author/company name, which stay the same on all of my pages.
Here is an example of what I am currently doing.:
exports.index = function(req, res){
res.render('index', {
siteTitle: 'My Website Title',
pageTitle: 'The Root Splash Page',
author: 'Cory Gross',
description: 'My app description',
indexSpecificData: someData
});
};
exports.home = function (req, res) {
res.render('home', {
siteTitle: 'My Website Title',
pageTitle: 'The Home Page',
author: 'Cory Gross',
description: 'My app description',
homeSpecificData: someOtherData
});
};
I would like to be able to define variables like my site's title, description, author, etc in one place and have them accessible in my layouts/templates through EJS without having to pass them as options to each call to res.render. Is there a way to do this and still allow me to pass in other variables specific to each page?
After having a chance to study the Express 3 API Reference a bit more I discovered what I was looking for. Specifically the entries for app.locals and then a bit farther down res.locals held the answers I needed.
I discovered for myself that the function app.locals takes an object and stores all of its properties as global variables scoped to the application. These globals are passed as local variables to each view. The function res.locals, however, is scoped to the request and thus, response local variables are accessible only to the view(s) rendered during that particular request/response.
So for my case in my app.js what I did was add:
app.locals({
site: {
title: 'ExpressBootstrapEJS',
description: 'A boilerplate for a simple web application with a Node.JS and Express backend, with an EJS template with using Twitter Bootstrap.'
},
author: {
name: 'Cory Gross',
contact: 'CoryG89#gmail.com'
}
});
Then all of these variables are accessible in my views as site.title, site.description, author.name, author.contact.
I could also define local variables for each response to a request with res.locals, or simply pass variables like the page's title in as the optionsparameter in the render call.
EDIT: This method will not allow you to use these locals in your middleware. I actually did run into this as Pickels suggests in the comment below. In this case you will need to create a middleware function as such in his alternative (and appreciated) answer. Your middleware function will need to add them to res.locals for each response and then call next. This middleware function will need to be placed above any other middleware which needs to use these locals.
EDIT: Another difference between declaring locals via app.locals and res.locals is that with app.locals the variables are set a single time and persist throughout the life of the application. When you set locals with res.locals in your middleware, these are set everytime you get a request. You should basically prefer setting globals via app.locals unless the value depends on the request req variable passed into the middleware. If the value doesn't change then it will be more efficient for it to be set just once in app.locals.
You can do this by adding them to the locals object in a general middleware.
app.use(function (req, res, next) {
res.locals = {
siteTitle: "My Website's Title",
pageTitle: "The Home Page",
author: "Cory Gross",
description: "My app's description",
};
next();
});
Locals is also a function which will extend the locals object rather than overwriting it. So the following works as well
res.locals({
siteTitle: "My Website's Title",
pageTitle: "The Home Page",
author: "Cory Gross",
description: "My app's description",
});
Full example
var app = express();
var middleware = {
render: function (view) {
return function (req, res, next) {
res.render(view);
}
},
globalLocals: function (req, res, next) {
res.locals({
siteTitle: "My Website's Title",
pageTitle: "The Root Splash Page",
author: "Cory Gross",
description: "My app's description",
});
next();
},
index: function (req, res, next) {
res.locals({
indexSpecificData: someData
});
next();
}
};
app.use(middleware.globalLocals);
app.get('/', middleware.index, middleware.render('home'));
app.get('/products', middleware.products, middleware.render('products'));
I also added a generic render middleware. This way you don't have to add res.render to each route which means you have better code reuse. Once you go down the reusable middleware route you'll notice you will have lots of building blocks which will speed up development tremendously.
For Express 4.0 I found that using application level variables works a little differently & Cory's answer did not work for me.
From the docs: http://expressjs.com/en/api.html#app.locals
I found that you could declare a global variable for the app in
app.locals
e.g
app.locals.baseUrl = "http://www.google.com"
And then in your application you can access these variables & in your express middleware you can access them in the req object as
req.app.locals.baseUrl
e.g.
console.log(req.app.locals.baseUrl)
//prints out http://www.google.com
In your app.js you need add something like this
global.myvar = 100;
Now, in all your files you want use this variable, you can just access it as myvar
One way to do this by updating the app.locals variable for that app in app.js
Set via following
var app = express();
app.locals.appName = "DRC on FHIR";
Get / Access
app.listen(3000, function () {
console.log('[' + app.locals.appName + '] => app listening on port 3001!');
});
Elaborating with a screenshot from #RamRovi example with slight enhancement.
you can also use "global"
Example:
declare like this :
app.use(function(req,res,next){
global.site_url = req.headers.host; // hostname = 'localhost:8080'
next();
});
Use like this:
in any views or ejs file
<%
console.log(site_url);
%>
in js files
console.log(site_url);
With the differents answers, I implemented this code to use an external file JSON loaded in "app.locals"
Parameters
{
"web": {
"title" : "Le titre de ma Page",
"cssFile" : "20200608_1018.css"
}
}
Application
var express = require('express');
var appli = express();
var serveur = require('http').Server(appli);
var myParams = require('./include/my_params.json');
var myFonctions = require('./include/my_fonctions.js');
appli.locals = myParams;
EJS Page
<!DOCTYPE html>
<html lang="fr">
<head>
<meta charset="UTF-8">
<title><%= web.title %></title>
<link rel="stylesheet" type="text/css" href="/css/<%= web.cssFile %>">
</head>
</body>
</html>
Hoping it will help
What I do in order to avoid having a polluted global scope is to create a script that I can include anywhere.
// my-script.js
const ActionsOverTime = require('#bigteam/node-aot').ActionsOverTime;
const config = require('../../config/config').actionsOverTime;
let aotInstance;
(function () {
if (!aotInstance) {
console.log('Create new aot instance');
aotInstance = ActionsOverTime.createActionOverTimeEmitter(config);
}
})();
exports = aotInstance;
Doing this will only create a new instance once and share that everywhere where the file is included. I am not sure if it is because the variable is cached or of it because of an internal reference mechanism for the application (that might include caching). Any comments on how node resolves this would be great.
Maybe also read this to get the gist on how require works:
http://fredkschott.com/post/2014/06/require-and-the-module-system/