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
• Rust variable interpolation: Embed Rust expressions using #{expr} syntax
• Zero runtime overhead: Static strings when no interpolation is used
• Clear error messages: Points to the exact location of syntax errors

Usage

Add to your Cargo.toml:

[dependencies]
viewpoint-js = "0.2"
viewpoint-js-core = "0.2"  # Required for interpolation

Simple Expressions

use viewpoint_js::js;

// Returns &'static str
let code = js!{ 1 + 2 };
let code = js!{ () => window.innerWidth };
let code = js!{
    (() => {
        const items = document.querySelectorAll('li');
        return items.length;
    })()
};

Interpolation

Use #{expr} to embed Rust expressions into JavaScript:

use viewpoint_js::js;
use viewpoint_js_core::ToJsValue;

let selector = ".my-class";
let code = js!{ document.querySelector(#{selector}) };
// Produces: format!(...) that results in "document.querySelector(\".my-class\")"

let count = 42;
let code = js!{ Array(#{count}).fill(0) };
// Produces: "Array(42).fill(0)"

Compile-Time Errors

Invalid JavaScript produces compile-time errors:

use viewpoint_js::js;

// This won't compile!
let code = js!{ function( };

Supported Types for Interpolation

The following types implement ToJsValue:

• Integers: i8, i16, i32, i64, i128, isize, u8, u16, u32, u64, u128, usize
• Floats: f32, f64 (handles NaN, Infinity, -Infinity)
• Boolean: bool
• Strings: String, &str (properly escaped)
• Option: Option<T> where T: ToJsValue (produces value or null)
• JSON: serde_json::Value (with json feature)

Features

• json - Enable serde_json::Value support for interpolation

License

MIT