ssr + wasm compile warning

CHANGELOG.md

@@ -3,6 +3,12 @@
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.10.10] - 2024-05-10
+
+### Change 🔥
+
+- Added compile-time warning when you use `ssr` feature with `wasm32`. You can enable `wasm_ssr` to remove the warning.
+
 ## [0.10.9] - 2024-04-27
 
 ### Fixes 🍕

Cargo.toml

@@ -146,6 +146,7 @@ serde = ["dep:serde", "serde_json"]
 spin = ["dep:leptos-spin", "dep:http1"]
 ssr = []
 msgpack = ["dep:rmp-serde", "dep:serde"]
+wasm_ssr = []
 
 [package.metadata.docs.rs]
 features = ["math", "docs", "ssr", "prost", "serde"]

build.rs

@@ -0,0 +1,17 @@
+use std::env;
+
+fn main() {
+    let ssr = env::var("CARGO_FEATURE_SSR").is_ok();
+    let wasm_ssr = env::var("CARGO_FEATURE_WASM_SSR").is_ok();
+    let wasm32 = env::var("CARGO_CFG_TARGET_ARCH").expect("should be present in the build script")
+        == "wasm32";
+    if ssr && wasm32 && !wasm_ssr {
+        println!(
+            "cargo::warning=You have enabled the `ssr` feature for a wasm32 target. \
+This is probably not what you want. Please check https://leptos-use.rs/server_side_rendering.html \
+for how to use the `ssr` feature correctly.\n \
+If you're building for wasm32 on the server you can enable the `wasm_ssr` feature to get rid of \
+this warning."
+        );
+    }
+}

docs/book/src/server_side_rendering.md

@@ -54,6 +54,13 @@ By adding `"leptos-use/ssr"` to the `ssr` feature of your project, it will only
 be enabled when your project is built with `ssr`, and you will get the server
 functions server-side, and the client functions client-side.
 
+## WASM on the server
+
+If you enable `ssr` in your project on a `wasm32` target architecture, you will get
+a compile-time warning in the console because it is a common mistake that users enable `ssr` globally.
+If you're using `wasm32` on the server however you can safely disable this warning by
+enabling the `wasm_ssr` feature together with `ssr`.
+
 ## Functions with Target Elements
 
 A lot of functions like `use_resize_observer` and `use_element_size` are only useful when a target HTML/SVG element is