freeCodeCamp/curriculum/challenges/chinese/06-quality-assurance/advanced-node-and-express/set-up-a-template-engine.md

id	title	challengeType	forumTopicId	dashedName
5895f700f9fc0f352b528e63	Set up a Template Engine	2	301564	set-up-a-template-engine

--description--

As a reminder, this project is built upon the following starter project on Repl.it, or clone from GitHub.

A template engine enables you to use static template files (such as those written in Pug) in your app. At runtime, the template engine replaces variables in a template file with actual values which can be supplied by your server. Then it transforms the template into a static HTML file that is sent to the client. This approach makes it easier to design an HTML page and allows for displaying variables on the page without needing to make an API call from the client.

Add pug@~3.0.0 as a dependency in your package.json file.

Express needs to know which template engine you are using. We will use the set method to assign pug as the view engine property's value: app.set('view engine', 'pug')

Your page will not load until you correctly render the index file in the views/pug directory.

Change the argument of the res.render() declaration in the / route to be the file path to the views/pug directory. The path can be a relative path (relative to views), or an absolute path, and does not require a file extension.

If all went as planned, your app home page will stop showing the message "Pug template is not defined." and will now display a message indicating you've successfully rendered the Pug template!

Submit your page when you think you've got it right. If you're running into errors, you can check out the project completed up to this point here.

--hints--

Pug should be a dependency.

(getUserInput) =>
  $.get(getUserInput('url') + '/_api/package.json').then(
    (data) => {
      var packJson = JSON.parse(data);
      assert.property(
        packJson.dependencies,
        'pug',
        'Your project should list "pug" as a dependency'
      );
    },
    (xhr) => {
      throw new Error(xhr.statusText);
    }
  );

View engine should be Pug.

(getUserInput) =>
  $.get(getUserInput('url') + '/_api/server.js').then(
    (data) => {
      assert.match(
        data,
        /('|")view engine('|"),( |)('|")pug('|")/gi,
        'Your project should set Pug as a view engine'
      );
    },
    (xhr) => {
      throw new Error(xhr.statusText);
    }
  );

Use the correct ExpressJS method to render the index page from the response.

(getUserInput) =>
  $.get(getUserInput('url') + '/').then(
    (data) => {
      assert.match(
        data,
        /FCC Advanced Node and Express/gi,
        'You successfully rendered the Pug template!'
      );
    },
    (xhr) => {
      throw new Error(xhr.statusText);
    }
  );

Pug should be working.

(getUserInput) =>
  $.get(getUserInput('url') + '/').then(
    (data) => {
      assert.match(
        data,
        /pug-success-message/gi,
        'Your projects home page should now be rendered by pug with the projects .pug file unaltered'
      );
    },
    (xhr) => {
      throw new Error(xhr.statusText);
    }
  );

--solutions--

/**
  Backend challenges don't need solutions, 
  because they would need to be tested against a full working project. 
  Please check our contributing guidelines to learn more.
*/