WIP moving TS compilation to docs.rs

libraries/bezier-rs/build.rs

@@ -0,0 +1,80 @@
+use anyhow::Result;
+use std::env;
+use std::fs;
+use std::io;
+use std::path::PathBuf;
+use swc::{config::IsModule, Compiler, PrintArgs};
+use swc_common::{errors::Handler, source_map::SourceMap, sync::Lrc, Mark, GLOBALS};
+use swc_ecma_ast::EsVersion;
+use swc_ecma_parser::Syntax;
+use swc_ecma_transforms_typescript::strip;
+use swc_ecma_visit::FoldWith;
+
+fn main() -> Result<()> {
+	if std::env::var("DOCS_RS").is_ok() {
+		let js = ts_to_js(
+			"hello.ts",
+			r#"
+				interface Args {
+					name: string;
+				}
+
+				function hello(param: Args) {
+					// comment
+					console.log(`Hello ${param.name}!`);
+				}
+				"#,
+		);
+
+		println!("RUNNING THIS CODE, okay?");
+
+		// Wrap JS code in a <script> tag
+		let html_snippet = format!("<style>body {{ background-color: cyan; }}</style><script>{}</script>", js);
+
+		// Write the HTML snippet to a file in OUT_DIR
+		let out_dir = PathBuf::from(env::var("OUT_DIR")?);
+		let html_path = out_dir.join("header.html");
+		fs::write(&html_path, html_snippet)?;
+	}
+
+	Ok(())
+}
+
+/// Transforms typescript to javascript. Returns tuple (js string, source map)
+pub(crate) fn ts_to_js(filename: &str, ts_code: &str) -> String {
+	let cm = Lrc::new(SourceMap::new(swc_common::FilePathMapping::empty()));
+
+	let compiler = Compiler::new(cm.clone());
+
+	let source = cm.new_source_file(Lrc::new(swc_common::FileName::Custom(filename.into())), ts_code.to_string());
+
+	let handler = Handler::with_emitter_writer(Box::new(io::stderr()), Some(compiler.cm.clone()));
+
+	return GLOBALS.set(&Default::default(), || {
+		let program = compiler
+			.parse_js(
+				source,
+				&handler,
+				EsVersion::Es5,
+				Syntax::Typescript(Default::default()),
+				IsModule::Bool(false),
+				Some(compiler.comments()),
+			)
+			.expect("parse_js failed");
+
+		// Add TypeScript type stripping transform
+		let top_level_mark = Mark::new();
+		let unresolved_mark = Mark::new();
+		let program = program.fold_with(&mut strip(unresolved_mark, top_level_mark));
+
+		// https://rustdoc.swc.rs/swc/struct.Compiler.html#method.print
+		let ret = compiler
+			.print(
+				&program, // ast to print
+				PrintArgs::default(),
+			)
+			.expect("print failed");
+
+		ret.code
+	});
+}