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: '[email protected]'
}
});
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 options
parameter 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
.