There are two methods for rendering files or strings in Hexo: the asynchronous hexo.render.render method and the synchronous hexo.render.renderSync method. Unsurprisingly, the two methods are very similar so only the asynchronous hexo.render.render will be further discussed in the below paragraphs.

Render a String

When rendering a string, you must specify an engine to let Hexo know which rendering engine it should use.

hexo.render.render({text: 'example', engine: 'swig'}).then(function(result){
  // ...
});

Render a File

When rendering a file, it’s not necessary to specify an engine because Hexo will detect the relevant rendering engine automatically based on the extension of the file. Of course, you are also allowed to explicitly define the engine.

hexo.render.render({path: 'path/to/file.swig'}).then(function(result){
  // ...
});

Render Options

You can pass in an options object as the second argument.

hexo.render.render({text: ''}, {foo: 'foo'}).then(function(result){
  // ...
});

after_render Filters

When rendering is complete, Hexo will execute the corresponding after_render filters. For example, we can use this feature to implement a JavaScript minifier.

var UglifyJS = require('uglify-js');
hexo.extend.filter.register('after_render:js', function(str, data){
  var result = UglifyJS.minify(str);
  return result.code;
});

Check Whether a File is Renderable

You can use the isRenderable or isRenderableSync method to check whether a file path is renderable. Only when a corresponding renderer has been registered will this method return true.

hexo.render.isRenderable('layout.swig') // true
hexo.render.isRenderable('image.png') // false

Get the Output Extension

Use the getOutput method to get the extension of the rendered output. If a file is not renderable, the method will return an empty string.

hexo.render.getOutput('layout.swig') // html
hexo.render.getOutput('image.png') // '''