EJS-Lint

Linter/Syntax Checker for EJS Templates.

This was born out of mde/ejs #119 and the frustration of the unhelpful errors thrown if you make a simple syntax error inside a scriptlet tag.

Features

EJS-Lint parses scriptlet tags (<%, %>, <%_, _%>, and -%>) and expression tags (<%= and <%-).

Note: This linter does not attempt to check for unclosed EJS tags, so if you get an error Unexpected token with a line number that doesn't contain any scriptlets, you most likely forgot to close a tag earlier.

It will error out if it encounters an old-style includes (<% include filename %>) by default, but will tolerate them if the --preprocessor-include/preprocessorInclude option is set. It does not lint included files regardless of the method of inclusion.

Using await inside your ejs template will also throw an error by default - use option --await/await to allow usage of await in the template.

It can work with custom delimiters, just pass it in the options (if using the API) or pass the --delimiter (-d) flag on the CLI.

Installation

To install globally, for command-line use:

npm install -g ejs-lint

How it Works

EJS-Lint replaces everything outside a scriptlet tag with whitespace (to retain line & column numbers) and then runs the resulting (hopefully) valid JS through node-syntax-error to check for errors.

We use rewire to load EJS. This allows us to access Template.parseTemplateText(), an internal function that parses the string and splits it into an array.

Why can't EJS do this? At EJS, we try to keep the library lightweight. EJS-Lint uses acorn which is too large a dependency for EJS.

CLI

Usage:
 ejslint <file> [-d=?]

  If no file is specified, reads from stdin

Options:
  --help                  Show help                                            [boolean]
  --version               Show version number                                  [boolean]
  -d, --delimiter         Specify a custom delimiter ( i.e. <? instead of <% ) [string]
  --preprocessor-include  Allow old (pre-EJS v3) preprocessor-style includes   [boolean]
  --await                 Allow usage of await inside template                 [boolean]

API

Require:

const ejsLint = require('ejs-lint');

Then do ejsLint(text, options); where text is the EJS template and options are the EJS options (can additionally set preprocessorInclude to allow for old-style includes or set await to allow usage of await inside the template). This returns a node-syntax-error object that you can parse.

License

MIT