bugfix(bindgen-target-dir): use PathBuf to join

the old code are hard coded path with "/", which may cause error
on windows, thus changing to use PathBuf.join.

fixing #414

src/bindgen.rs

@@ -5,6 +5,7 @@ use emoji;
 use error::Error;
 use progressbar::Step;
 use slog::Logger;
+use std::env;
 use std::path::{Path, PathBuf};
 use std::process::Command;
 use target;
@@ -126,10 +127,17 @@ pub fn wasm_bindgen_build(
     let out_dir = out_dir.to_str().unwrap();
 
     if let Some(wasm_bindgen_path) = wasm_bindgen_path(log, path) {
-        let wasm_path = format!(
+        let target_path = match env::var("CARGO_TARGET_DIR") {
-            "target/wasm32-unknown-unknown/{}/{}.wasm",
+            Ok(path) => PathBuf::from(&path),
-            release_or_debug, binary_name
+            Err(_) => PathBuf::from("target"),
-        );
+        };
+        let mut wasm_path = target_path
+            .join("wasm32-unknown-unknown")
+            .join(release_or_debug)
+            .join(binary_name);
+        wasm_path.set_extension("wasm");
+        let wasm_path = wasm_path.display().to_string();
+
         let dts_arg = if disable_dts {
             "--no-typescript"
         } else {

tests/all/build.rs

@@ -32,9 +32,6 @@ fn it_should_build_js_hello_world_example() {
     ])
     .unwrap();
     let logger = logger::new(&cli.cmd, cli.verbosity).unwrap();
-    let result = command::run_wasm_pack(cli.cmd, &logger);
+    command::run_wasm_pack(cli.cmd, &logger)
-    assert!(
+        .expect("running wasm-pack in a js-hello-world directory should succeed.");
-        result.is_ok(),
-        "running wasm-pack in a js-hello-world directory should succeed.",
-    );
 }