yeahjs

yeahjs

A tiny, modern, fast implementation of EJS (Embedded JavaScript Templates). A nearly drop-in replacement for ejs with a few intentional limitations.

Example

<ul>
<% for (let word of locals.items) { -%>
  <li><%= word %></li>
<% } -%>
</ul>

const template = yeahjs.compile(ejs);
const output = template({items: ['flour', 'water', 'salt']});

<ul>
  <li>flour</li>
  <li>water</li>
  <li>salt</li>
</ul>

Compared to ejs

There are a few key differences that allow yeahjs to be so small and fast:

• Strict mode only (no with keyword in compiled functions).
• Only static path includes (include('header.ejs'), but not include(dir + file)).
• File handling not included — provide it with read and resolve options (see example).

Otherwise yeahjs produces identical output to ejs.

Usage

const template = yeahjs.compile(ejs, options);

Returns a function of the form (data) => content. Options:

• localsName: the namespace to use for accessing template data (locals by default for <%= locals.foo %>).
• locals: an array of variables to access directly (e.g. ['foo'] will allow <%= foo %> instead of <%= locals.foo %>).
• context: an object to use as this in templates (null by default).
• escape: a custom escaping function for values inside <%= ... %> (escapes XML by default).
• async: if true, generates an async function to make it possible to use await inside templates (false by default).
• filename: the file name of the template if present (used for resolving includes).
• read: a function of the form (filename) => content for reading includes (e.g. from file system in Node).
• resolve: a function of the form (parentPath, includePath) => path for resolving include paths.
• cache: an object to cache compiled includes in for faster compilation; reuse between compile runs for best performance ({} by default).

EJS cheatsheet

• <%= value %>: output the value (escaped).
• <%- value %>: output the value (raw).
• <% code %>: use arbitrary JavaScript.
• <%_ code %>: use arbitrary JavaScript and strip whitespace on the same line before the tag.
• ... _%>: strip whitespace and a single line break on the same line after the tag.
• ... -%>: strip a single line break immediately after the tag.
• <%%, %%>: output literal <% or %>.
• <%# comment %>: comment (ignored).
• <%- include('path/to/template.ejs', {foo: bar}) %>: include another template, optionally passing data.

File handling

An example of using read, resolve and filename options in Node.js to process includes:

const {readFileSync} = require('fs');
const {join, dirname} = require('path');

const template = yeahjs.compile(`<%- include('../bar.html') %>`, {
    filename: 'foo/foo.html',
    resolve: (parent, filename) => join(dirname(parent), filename),
    read: filename => readFileSync(filename, 'utf8')
});