rollup-plugin-underscorify

1.0.0 verified Mon Apr 27 auth: no javascript

A Rollup plugin (v1.0.0, single release) that converts Underscore templates into ES modules for use in Backbone/Marionette apps. Unlike other template compilers, it forces explicit namespace variable access (no `with` statement) to maintain ES2015 strict mode compatibility. Requires manual injection of Underscore or other libraries into template scope, as Rollup's module bundling can't guarantee global access. Minimal configuration with include/exclude patterns and custom variable name. Stable but essentially feature-complete.

Common errors

error Error: Cannot find module 'rollup-plugin-underscorify' ↓

cause Package not installed or only installed as devDependency but not available in build environment.

fix

Run npm install rollup-plugin-underscorify --save-dev and ensure node_modules path is correct.

error SyntaxError: Unexpected token 'export' ↓

cause Using CJS require with an ESM-only package.

fix

Use import syntax in your Rollup config (requires Rollup ESM config support).

error TypeError: underscorify is not a function ↓

cause Using named import `underscorify` instead of default import.

fix

Change import to import underscorify from 'rollup-plugin-underscorify'.

Warnings

gotcha Namespace variable (e.g., `p`) MUST be used inside templates to access data; raw property names like `<%= username %>` will be undefined. ↓

fix Always prefix data properties with the configured variable, e.g., `<%= p.username %>`.

gotcha Underscore (`_`) or any other library used inside templates must be explicitly passed in the data object. Rollup does not guarantee global import availability. ↓

fix Pass `_` as part of the template data, e.g., `tplData._ = _;`.

gotcha The plugin compiles templates to ES modules; ensure your Rollup config outputs a format (e.g., iife, umd) that supports module imports if used in browsers. ↓

fix Use a suitable `output.format` like 'iife' or 'umd'.

gotcha `with` statement is not used, so template code must reference data through the variable; this avoids strict mode issues but changes template syntax from standard Underscore templates. ↓

fix Always use variable prefix (e.g., `p.`) in template expressions.

Install

npm install rollup-plugin-underscorify

yarn add rollup-plugin-underscorify

pnpm add rollup-plugin-underscorify

Imports

default

wrong

const underscorify = require('rollup-plugin-underscorify')

correct

import underscorify from 'rollup-plugin-underscorify'

ESM-only; CJS require will cause undefined error.

underscorify

wrong

import { underscorify } from 'rollup-plugin-underscorify'

correct

import underscorify from 'rollup-plugin-underscorify'

Default export, not named.

Plugin config object

wrong

underscorify(['**/*.tpl'])

correct

underscorify({ include: ['**/*.tpl'], exclude: ['**/ignore.tpl'], variable: 'p' })

Options must be passed as an object, not an array.

Quickstart

Shows minimal Rollup config using the plugin to compile .tpl files into Underscore template modules.

import underscorify from 'rollup-plugin-underscorify';

export default {
  input: 'index.js',
  output: { file: 'bundle.js', format: 'iife' },
  plugins: [
    underscorify({
      include: ['**/*.tpl'],
      variable: 'p'
    })
  ]
};