feat(build): add first-class support for binary crates

src/bindgen.rs

@@ -28,49 +28,62 @@ pub fn wasm_bindgen_build(
 
     let out_dir = out_dir.to_str().unwrap();
 
-    let wasm_path = data
-        .target_directory()
-        .join("wasm32-unknown-unknown")
-        .join(release_or_debug)
-        .join(data.crate_name())
-        .with_extension("wasm");
-
-    let dts_arg = if disable_dts {
-        "--no-typescript"
-    } else {
-        "--typescript"
-    };
-    let bindgen_path = bindgen.binary("wasm-bindgen")?;
+    for target_name in data.targets() {
+        let wasm_path = {
+            let wasm_path = data
+                .target_directory()
+                .join("wasm32-unknown-unknown")
+                .join(release_or_debug);
+            let wasm_path = if data.is_example() {
+                wasm_path.join("examples")
+            } else {
+                wasm_path
+            };
+            wasm_path.join(target_name).with_extension("wasm")
+        };
 
-    let mut cmd = Command::new(&bindgen_path);
-    cmd.arg(&wasm_path)
-        .arg("--out-dir")
-        .arg(out_dir)
-        .arg(dts_arg);
+        if !wasm_path.exists() {
+            continue;
+        }
 
-    let target_arg = build_target_arg(target, &bindgen_path)?;
-    if supports_dash_dash_target(&bindgen_path)? {
-        cmd.arg("--target").arg(target_arg);
-    } else {
-        cmd.arg(target_arg);
-    }
+        let dts_arg = if disable_dts {
+            "--no-typescript"
+        } else {
+            "--typescript"
+        };
+        let bindgen_path = bindgen.binary("wasm-bindgen")?;
 
-    if let Some(value) = out_name {
-        cmd.arg("--out-name").arg(value);
-    }
+        let mut cmd = Command::new(&bindgen_path);
+        cmd.arg(&wasm_path)
+            .arg("--out-dir")
+            .arg(out_dir)
+            .arg(dts_arg);
 
-    let profile = data.configured_profile(profile);
-    if profile.wasm_bindgen_debug_js_glue() {
-        cmd.arg("--debug");
-    }
-    if !profile.wasm_bindgen_demangle_name_section() {
-        cmd.arg("--no-demangle");
-    }
-    if profile.wasm_bindgen_dwarf_debug_info() {
-        cmd.arg("--keep-debug");
+        let target_arg = build_target_arg(target, &bindgen_path)?;
+        if supports_dash_dash_target(&bindgen_path)? {
+            cmd.arg("--target").arg(target_arg);
+        } else {
+            cmd.arg(target_arg);
+        }
+
+        if let Some(value) = out_name {
+            cmd.arg("--out-name").arg(value);
+        }
+
+        let profile = data.configured_profile(profile);
+        if profile.wasm_bindgen_debug_js_glue() {
+            cmd.arg("--debug");
+        }
+        if !profile.wasm_bindgen_demangle_name_section() {
+            cmd.arg("--no-demangle");
+        }
+        if profile.wasm_bindgen_dwarf_debug_info() {
+            cmd.arg("--keep-debug");
+        }
+
+        child::run(cmd, "wasm-bindgen").context("Running the wasm-bindgen CLI")?;
     }
 
-    child::run(cmd, "wasm-bindgen").context("Running the wasm-bindgen CLI")?;
     Ok(())
 }
 

src/build/mod.rs

@@ -76,12 +76,13 @@ fn wasm_pack_local_version() -> Option<String> {
 pub fn cargo_build_wasm(
     path: &Path,
     profile: BuildProfile,
+    example: &Option<String>,
     extra_options: &[String],
 ) -> Result<(), Error> {
     let msg = format!("{}Compiling to Wasm...", emoji::CYCLONE);
     PBAR.info(&msg);
     let mut cmd = Command::new("cargo");
-    cmd.current_dir(path).arg("build").arg("--lib");
+    cmd.current_dir(path).arg("build");
     match profile {
         BuildProfile::Profiling => {
             // Once there are DWARF debug info consumers, force enable debug
@@ -100,6 +101,9 @@ pub fn cargo_build_wasm(
         }
     }
     cmd.arg("--target").arg("wasm32-unknown-unknown");
+    if let Some(example) = example {
+        cmd.arg("--example").arg(example);
+    }
     cmd.args(extra_options);
     child::run(cmd, "cargo build").context("Compiling your crate to WebAssembly failed")?;
     Ok(())

src/command/build.rs

@@ -34,6 +34,7 @@ pub struct Build {
     pub out_name: Option<String>,
     pub bindgen: Option<Download>,
     pub cache: Cache,
+    pub example: Option<String>,
     pub extra_options: Vec<String>,
 }
 
@@ -148,6 +149,10 @@ pub struct BuildOptions {
     /// Sets the output file names. Defaults to package name.
     pub out_name: Option<String>,
 
+    #[structopt(long = "example")]
+    /// Builds the specified example.
+    pub example: Option<String>,
+
     #[structopt(last = true)]
     /// List of extra options to pass to `cargo build`
     pub extra_options: Vec<String>,
@@ -167,6 +172,7 @@ impl Default for BuildOptions {
             profiling: false,
             out_dir: String::new(),
             out_name: None,
+            example: None,
             extra_options: Vec::new(),
         }
     }
@@ -178,7 +184,11 @@ impl Build {
     /// Construct a build command from the given options.
     pub fn try_from_opts(build_opts: BuildOptions) -> Result<Self, Error> {
         let crate_path = get_crate_path(build_opts.path)?;
-        let crate_data = manifest::CrateData::new(&crate_path, build_opts.out_name.clone())?;
+        let crate_data = manifest::CrateData::new(
+            &crate_path,
+            build_opts.out_name.clone(),
+            build_opts.example.clone(),
+        )?;
         let out_dir = crate_path.join(PathBuf::from(build_opts.out_dir));
 
         let dev = build_opts.dev || build_opts.debug;
@@ -203,6 +213,7 @@ impl Build {
             out_name: build_opts.out_name,
             bindgen: None,
             cache: cache::get_wasm_pack_cache()?,
+            example: build_opts.example,
             extra_options: build_opts.extra_options,
         })
     }
@@ -298,7 +309,12 @@ impl Build {
 
     fn step_build_wasm(&mut self) -> Result<(), Error> {
         info!("Building wasm...");
-        build::cargo_build_wasm(&self.crate_path, self.profile, &self.extra_options)?;
+        build::cargo_build_wasm(
+            &self.crate_path,
+            self.profile,
+            &self.example,
+            &self.extra_options,
+        )?;
 
         info!(
             "wasm built at {:#?}.",

src/command/test.rs

@@ -119,7 +119,7 @@ impl Test {
         } = test_opts;
 
         let crate_path = get_crate_path(path)?;
-        let crate_data = manifest::CrateData::new(&crate_path, None)?;
+        let crate_data = manifest::CrateData::new(&crate_path, None, None)?;
         let any_browser = chrome || firefox || safari;
 
         if !node && !any_browser {

src/manifest/mod.rs

@@ -39,6 +39,7 @@ pub struct CrateData {
     current_idx: usize,
     manifest: CargoManifest,
     out_name: Option<String>,
+    example: Option<String>,
 }
 
 #[doc(hidden)]
@@ -402,7 +403,11 @@ pub struct ManifestAndUnsedKeys {
 impl CrateData {
     /// Reads all metadata for the crate whose manifest is inside the directory
     /// specified by `path`.
-    pub fn new(crate_path: &Path, out_name: Option<String>) -> Result<CrateData, Error> {
+    pub fn new(
+        crate_path: &Path,
+        out_name: Option<String>,
+        example: Option<String>,
+    ) -> Result<CrateData, Error> {
         let manifest_path = crate_path.join("Cargo.toml");
         if !manifest_path.is_file() {
             bail!(
@@ -431,6 +436,7 @@ impl CrateData {
             manifest,
             current_idx,
             out_name,
+            example,
         })
     }
 
@@ -493,18 +499,30 @@ impl CrateData {
         Ok(())
     }
 
-    fn check_crate_type(&self) -> Result<(), Error> {
+    fn valid_targets(&self) -> impl Iterator<Item = &cargo_metadata::Target> {
+        fn valid(target: &cargo_metadata::Target, example: &Option<String>) -> bool {
+            if let Some(example) = example {
+                target.name == *example && target.kind.iter().any(|k| k == "example")
+            } else {
+                fn valid_kind(x: &str) -> bool {
+                    x == "cdylib" || x == "bin"
+                }
+                target.kind.iter().any(|x| valid_kind(x))
+            }
+        }
         let pkg = &self.data.packages[self.current_idx];
-        let any_cdylib = pkg
-            .targets
+        pkg.targets
             .iter()
-            .filter(|target| target.kind.iter().any(|k| k == "cdylib"))
-            .any(|target| target.crate_types.iter().any(|s| s == "cdylib"));
-        if any_cdylib {
+            .filter(move |target| valid(target, &self.example))
+    }
+
+    fn check_crate_type(&self) -> Result<(), Error> {
+        let any_valid = self.valid_targets().count() > 0;
+        if any_valid {
             return Ok(());
         }
         bail!(
-            "crate-type must be cdylib to compile to wasm32-unknown-unknown. Add the following to your \
+            "library crate-type must be cdylib to compile to wasm32-unknown-unknown. Add the following to your \
              Cargo.toml file:\n\n\
              [lib]\n\
              crate-type = [\"cdylib\", \"rlib\"]"
@@ -524,6 +542,22 @@ impl CrateData {
         }
     }
 
+    /// Get the target names that will be built for the current crate.
+    pub fn targets(&self) -> impl Iterator<Item = String> + '_ {
+        self.valid_targets().map(|x| {
+            if x.kind.iter().any(|x| x.ends_with("lib")) {
+                x.name.replace("-", "_")
+            } else {
+                x.name.clone()
+            }
+        })
+    }
+
+    /// Check if we are building an example.
+    pub fn is_example(&self) -> bool {
+        self.example.is_some()
+    }
+
     /// Get the prefix for output file names
     pub fn name_prefix(&self) -> String {
         match &self.out_name {

tests/all/build.rs

@@ -295,3 +295,62 @@ fn build_force() {
         .assert()
         .success();
 }
+
+#[test]
+fn bin_crate_behavior_identical() {
+    let fixture = utils::fixture::bin_crate();
+    fixture.install_local_wasm_bindgen();
+    fixture
+        .wasm_pack()
+        .arg("build")
+        .arg("--target")
+        .arg("nodejs")
+        .assert()
+        .success();
+    let native_output = fixture.command("cargo").arg("run").output().unwrap();
+    assert!(native_output.status.success());
+    assert_eq!(native_output.stdout, b"Hello, World\n");
+    let wasm_output = fixture.command("node").arg("pkg/foo.js").output().unwrap();
+    assert!(wasm_output.status.success());
+    assert_eq!(wasm_output.stdout, b"Hello, World\n");
+}
+
+#[test]
+fn multi_bin_crate_procs_all() {
+    let fixture = utils::fixture::multi_bin_crate();
+    fixture.install_local_wasm_bindgen();
+    fixture
+        .wasm_pack()
+        .arg("build")
+        .arg("--target")
+        .arg("nodejs")
+        .assert()
+        .success();
+    let pkg_path = |x: &str| {
+        let mut path = fixture.path.clone();
+        path.push("pkg");
+        path.push(x);
+        path
+    };
+    assert!(pkg_path("foo.js").exists());
+    assert!(pkg_path("sample.js").exists());
+}
+
+#[test]
+fn builds_examples() {
+    let fixture = utils::fixture::bin_example_crate();
+    fixture.install_local_wasm_bindgen();
+    fixture
+        .wasm_pack()
+        .arg("build")
+        .arg("--target")
+        .arg("nodejs")
+        .arg("--example")
+        .arg("example")
+        .assert()
+        .success();
+    let mut path = fixture.path.clone();
+    path.push("pkg");
+    path.push("example.js");
+    assert!(path.exists());
+}

tests/all/license.rs

@@ -12,7 +12,7 @@ fn it_copies_a_license_default_path() {
     let fixture = fixture::single_license();
     let out_dir = fixture.path.join("pkg");
     fs::create_dir(&out_dir).expect("should create pkg directory OK");
-    let crate_data = CrateData::new(&fixture.path, None);
+    let crate_data = CrateData::new(&fixture.path, None, None);
 
     assert!(license::copy_from_crate(&crate_data.unwrap(), &fixture.path, &out_dir).is_ok());
 
@@ -37,7 +37,7 @@ fn it_copies_a_license_provided_path() {
     let fixture = fixture::single_license();
     let out_dir = fixture.path.join("pkg");
     fs::create_dir(&out_dir).expect("should create pkg directory OK");
-    let crate_data = CrateData::new(&fixture.path, None);
+    let crate_data = CrateData::new(&fixture.path, None, None);
 
     assert!(license::copy_from_crate(&crate_data.unwrap(), &fixture.path, &out_dir).is_ok());
     let crate_license_path = fixture.path.join("LICENSE");
@@ -60,7 +60,7 @@ fn it_copies_all_licenses_default_path() {
     let fixture = fixture::dual_license();
     let out_dir = fixture.path.join("pkg");
     fs::create_dir(&out_dir).expect("should create pkg directory OK");
-    let crate_data = CrateData::new(&fixture.path, None);
+    let crate_data = CrateData::new(&fixture.path, None, None);
 
     assert!(license::copy_from_crate(&crate_data.unwrap(), &fixture.path, &out_dir).is_ok());
 
@@ -95,7 +95,7 @@ fn it_copies_all_licenses_provided_path() {
     let fixture = fixture::dual_license();
     let out_dir = fixture.path.join("pkg");
     fs::create_dir(&out_dir).expect("should create pkg directory OK");
-    let crate_data = CrateData::new(&fixture.path, None);
+    let crate_data = CrateData::new(&fixture.path, None, None);
 
     assert!(license::copy_from_crate(&crate_data.unwrap(), &fixture.path, &out_dir).is_ok());
 
@@ -131,7 +131,7 @@ fn it_copies_a_non_standard_license_provided_path() {
     let fixture = fixture::non_standard_license(license_file);
     let out_dir = fixture.path.join("pkg");
     fs::create_dir(&out_dir).expect("should create pkg directory OK");
-    let crate_data = CrateData::new(&fixture.path, None);
+    let crate_data = CrateData::new(&fixture.path, None, None);
 
     assert!(license::copy_from_crate(&crate_data.unwrap(), &fixture.path, &out_dir).is_ok());