Crate viewpoint_js 

Compile-time validated JavaScript macro for Viewpoint.

This crate provides a js! macro that validates JavaScript syntax at compile time, similar to how serde_json::json! validates JSON. This catches JavaScript syntax errors early, before they reach the browser.

Features

• Compile-time validation: JavaScript syntax errors are caught during compilation
• Value interpolation: Embed Rust expressions using #{expr} syntax (quoted/escaped)
• Raw interpolation: Inject pre-built JavaScript using @{expr} syntax (unquoted)
• Zero runtime overhead: Static strings when no interpolation is used
• Clear error messages: Points to the exact location of syntax errors

Usage

use viewpoint_js::js;
use viewpoint_js_core::ToJsValue; // Needed for value interpolation

// Simple expression - produces &'static str
let code = js!{ 1 + 2 };

// Arrow function
let code = js!{ () => window.innerWidth };

// With value interpolation (requires ToJsValue in scope)
let selector = ".my-class";
let code = js!{ document.querySelector(#{selector}) };

// With raw interpolation (inject JS expression as-is)
let selector_expr = "document.querySelectorAll('.item')";
let code = js!{ Array.from(@{selector_expr}) };

// Multi-line function
let code = js!{
    (() => {
        const items = document.querySelectorAll("li");
        return items.length;
    })()
};

Value Interpolation (#{expr})

Use #{expr} to embed Rust values into JavaScript. Values are automatically converted to JavaScript representations via the ToJsValue trait:

• Strings are quoted and escaped
• Numbers are inserted as-is
• Booleans become true or false
• Option::None becomes null

Raw Interpolation (@{expr})

Use @{expr} to inject pre-built JavaScript expressions directly without quoting or escaping. The expression must return something that implements AsRef<str>. This is useful for:

• Injecting dynamically-built selector expressions
• Composing JavaScript from multiple parts
• Including pre-validated JavaScript fragments

Macros

js

A macro that validates JavaScript syntax at compile time.