@memberjunction/templates

Server-side template rendering engine for MemberJunction, built on Nunjucks. Extends TemplateEngineBase with rendering capabilities, custom filters, and MJ-specific extensions for AI prompt integration and recursive template embedding.

Architecture

graph TD
    subgraph "@memberjunction/templates"
        A[TemplateEngineServer] --> B[Nunjucks Environment]
        A --> C[Template Cache]
        A --> D[TemplateEntityLoader]
        B --> E[Custom Filters]
        B --> F[Extensions]
        F --> G[AIPrompt Extension]
        F --> H[TemplateEmbed Extension]
    end

    subgraph "Base Layer"
        I["TemplateEngineBase<br/>(from base-types)"]
    end

    A -->|extends| I

    subgraph "Rendering"
        J[Template Entity] --> K[Validation]
        K --> L[Merge Defaults]
        L --> M[Nunjucks Render]
        M --> N[TemplateRenderResult]
    end

    style A fill:#2d6a9f,stroke:#1a4971,color:#fff
    style B fill:#2d8659,stroke:#1a5c3a,color:#fff
    style C fill:#7c5295,stroke:#563a6b,color:#fff
    style G fill:#b8762f,stroke:#8a5722,color:#fff
    style H fill:#b8762f,stroke:#8a5722,color:#fff
    style I fill:#2d6a9f,stroke:#1a4971,color:#fff
    style N fill:#2d8659,stroke:#1a5c3a,color:#fff

Overview

This package is the server-side rendering engine for MemberJunction templates. It is NOT used within Angular applications despite using Angular Universal internally for compilation.

Key capabilities:

• Nunjucks Rendering: Full Nunjucks template syntax with async support
• Parameter Validation: Validates input data against template parameter definitions before rendering
• Default Value Merging: Automatically applies parameter defaults with content-specific overrides
• Template Caching: Compiled Nunjucks templates are cached for performance
• Custom Filters: json, jsoninline, and jsonparse filters for JSON manipulation
• Extensible: Plugin system via TemplateExtensionBase for custom Nunjucks tags
• AI Prompt Extension: Execute AI prompts inline within templates
• Template Embedding: Recursively embed templates within other templates

Installation

npm install @memberjunction/templates

Usage

Rendering Templates

import { TemplateEngineServer } from '@memberjunction/templates';

const engine = TemplateEngineServer.Instance;
await engine.Config(false, contextUser);

// Find and render a template
const template = engine.FindTemplate('Welcome Email');
const content = template.Content[0]; // First content variant

const result = await engine.RenderTemplate(template, content, {
    userName: 'John Doe',
    companyName: 'Acme Corp'
});

if (result.Success) {
    console.log(result.Output); // Rendered HTML/text
} else {
    console.error(result.Message); // Validation or rendering error
}

Simple Template Rendering

For ad-hoc templates not stored in the database:

const result = await engine.RenderTemplateSimple(
    'Hello {{ name }}, welcome to {{ company }}!',
    { name: 'Jane', company: 'MemberJunction' }
);
// result.Output: "Hello Jane, welcome to MemberJunction!"

By default, output is HTML-escaped. For plain-text contexts such as email subject lines — where Acme & Co must not become Acme & Co — opt out with the autoescape option:

const subject = await engine.RenderTemplateSimple(
    '{{ company }} — your invite',
    { company: 'Acme & Co' },
    { autoescape: false }
);
// subject.Output: "Acme & Co — your invite"  (no entity encoding)

Custom Nunjucks Filters

The engine provides built-in filters for JSON operations:

{# Convert object to formatted JSON #}
{{ userData | json }}

{# Compact JSON output #}
{{ userData | jsoninline }}

{# Parse a JSON string back to object #}
{% set parsed = jsonString | jsonparse %}

Template Extensions

Extensions are registered via the MJ class factory:

graph LR
    A[TemplateExtensionBase] --> B[AIPrompt Extension]
    A --> C[TemplateEmbed Extension]
    A --> D[Custom Extensions]

    style A fill:#2d6a9f,stroke:#1a4971,color:#fff
    style B fill:#2d8659,stroke:#1a5c3a,color:#fff
    style C fill:#2d8659,stroke:#1a5c3a,color:#fff
    style D fill:#7c5295,stroke:#563a6b,color:#fff

• AIPrompt Extension: Executes AI prompts inline within templates using {% aiprompt %} tags
• TemplateEmbed Extension: Embeds other templates within a template using {% templateembed %} tags

API Reference

TemplateEngineServer

Member	Type	Description
Instance	static getter	Singleton instance
Config()	method	Load metadata and initialize Nunjucks environment
RenderTemplate()	method	Render a stored template with validation
RenderTemplateSimple()	method	Render an ad-hoc template string
AddTemplate()	method	Add a template to the Nunjucks loader
SetupNunjucks()	method	Re-initialize the Nunjucks environment
ClearTemplateCache()	method	Clear cached compiled templates

Rendering Process

1. Validation: Input data is validated against template parameter definitions
2. Default Merging: Missing parameters receive default values (content-specific defaults override global defaults)
3. Compilation: Template text is compiled by Nunjucks (cached after first compile)
4. Rendering: Nunjucks processes the template with merged data
5. Result: Returns TemplateRenderResult with Success, Output, and optional Message

Dependencies

Package	Purpose
@memberjunction/templates-base-types	Base engine and result types
@memberjunction/core	UserInfo, logging utilities
@memberjunction/core-entities	Template entity types
@memberjunction/global	Class factory for extensions
@memberjunction/ai	AI integration for prompts
@memberjunction/ai-core-plus	AI core utilities
nunjucks	Template rendering engine

License

ISC