To determine whether we are in production or development mode, we have an available variable in the template called env .

Unfortunately, the hexo documentation does not give us details of what may be there.

However, to see what is sitting there, you only need to print the contents of this variable in the template

Example themes/some-theme/layout/layout.ejs

<! DOCTYPE html > < pre > < code > <%= JSON.stringify(env, null, 2) %> </ code > </ pre >

Then opening localhost:4000 you will see this result.

As we can see, hexo env contains an env property which represents the application mode in which it started.

In hexo server mode will be development , and when generating a static page to change the value of env.env just add NODE_ENV=production before hexo generate

NODE_ENV=production hexo generate

Now we can use the acquired variable, for example, to add analytics only in production mode.

<% if (env.env === 'production') { %> < script async src = " https://www.googletagmanager.com/gtag/js?id=GA_TRACKING_ID " > </ script > < script > window . dataLayer = window . dataLayer || [ ] ; function gtag ( ) { dataLayer . push ( arguments ) ; } gtag ( 'js' , new Date ( ) ) ; gtag ( 'config' , 'GA_TRACKING_ID' ) ; </ script > <% } %>

That’s all, goodbye.