@withstudiocms/template-lang


A simple TypeScript ESM template language for HTML emails, similar to Handlebars but focused on simplicity and database data integration.

Features

- 🚀 Simple {{variable}} syntax for variable interpolation
- 🔍 Support for nested properties with dot notation ({{user.name}})
- ⚡ TypeScript with full ESM support
- 🛡️ Strict mode for error handling
- 🎯 Designed specifically for email templates and DB data
- 📦 Zero dependencies

Installation

``bash
npm install @withstudiocms/template-lang
`

Basic Usage

`typescript
import TemplateEngine from '@withstudiocms/template-lang';

const engine = new TemplateEngine();

const template = "Hello {{name}}! Welcome to {{company.name}}.";
const data = {
name: "John Doe",
company: {
name: "Acme Corp"
}
};

const result = engine.render(template, data);
console.log(result); // "Hello John Doe! Welcome to Acme Corp."
`

Template Syntax

$3


`html

Hello {{user.firstName}} {{user.lastName}}!

Your order #{{order.id}} total is ${{order.total}}

`

$3

`html

Shipping to: {{user.address.street}}, {{user.address.city}}

`

API Reference

$3

#### Constructor
`typescript
new TemplateEngine(options?: TemplateOptions)
`

#### Methods

render(template: string, data: TemplateData): string
Renders a template with the provided data.

compile(template: string): (data: TemplateData) => string
Compiles a template into a reusable function.

hasVariables(template: string): boolean
Checks if a template contains any variables.

getVariables(template: string): string[]
Returns an array of all variable names in the template.

setOptions(options: Partial): void
Updates the engine options.

$3

`typescript
interface TemplateOptions {
strict?: boolean; // Throw error on missing variables (default: false)
defaultValue?: string; // Default value for missing variables (default: '')
}
`

Examples

$3


`typescript
const emailTemplate =

Hello {{user.name}}!

Your order #{{order.id}} has been confirmed.

Total: {{order.total}}

;

const data = {
subject: "Order Confirmation",
user: { name: "John Doe" },
order: { id: "12345", total: "99.99" }
};

const html = engine.render(emailTemplate, data);
`

$3


`typescript
const strictEngine = new TemplateEngine({ strict: true });

// This will throw an error if 'missingVar' is not in data
try {
const result = strictEngine.render("Hello {{missingVar}}!", {});
} catch (error) {
console.log("Variable not found:", error.message);
}
`

$3


`typescript
const engine = new TemplateEngine({ defaultValue: "[NOT SET]" });
const result = engine.render("Hello {{name}}!", {});
// Result: "Hello [NOT SET]!"
`

$3

`typescript
// Compile once, use multiple times
const compiled = engine.compile("Hello {{name}}!");

const result1 = compiled({ name: "Alice" });
const result2 = compiled({ name: "Bob" });
``

Use Cases

Perfect for:
- HTML email templates
- Dynamic content generation from database data
- Simple templating needs without complex logic
- ESM-first TypeScript projects

License

MIT