@da1z/prompt

A super lightweight, fully typesafe string templating library. Built for prompts, useful everywhere.

Zero dependencies. Zero config. Full type inference.

The entire library is ~6 lines of runtime code. TypeScript does the heavy lifting, variable names are extracted from your template at compile time, so typos and missing values are caught before your code ever runs.

Installation

npm install @da1z/prompt

Quick Start

import { createTemplate } from "@da1z/prompt";

const greet = createTemplate("Hello, {name}!" as const);

greet({ name: "World" });
// => "Hello, World!"

That's it. No DSL to learn, no config files, no runtime overhead.

Why?

Prompt templates are just strings with holes. Most templating engines bring parsers, ASTs, and a pile of dependencies for something that should be trivial.

@da1z/prompt gives you:

• Type-safe variables -- placeholder names are inferred from the template string
• Strict checking -- missing keys, extra keys, and typos are compile-time errors
• Tiny footprint -- ships less code than this README

Type Safety in Action

const template = createTemplate("User: {user}, Role: {role}" as const);

template({ user: "Kira", role: "admin" }); // OK
template({ user: "Kira" }); // TS error: missing "role"
template({ user: "Kira", role: "admin", x: "?" }); // TS error: unknown key

API

createTemplate(template)

Takes a string literal and returns a function that accepts a strictly typed object of template variables and returns the interpolated string.

• Placeholder format: {variableName}
• Repeated placeholders are filled with the same value
• No placeholders? The returned function accepts an empty object

License

MIT