feat(flag): add scope flag to init subcommand

npm allows scopes to avoid name collisions. In order to support this
optional feature a flag has been added so that the name in the generated
package.json is correct.

Example for a package named wasm-add:

```bash
wasm-pack init
```

package.json

```json
{
  "name": "wasm-add"
}
```

```bash
wasm-pack init --scope mgattozzi
```

package.json

```json
{
  "name": "@mgattozzi/wasm-add"
}
```

src/main.rs

@@ -24,7 +24,11 @@ struct Cli {
 enum Command {
     #[structopt(name = "init")]
     /// 🐣  initialize a package.json based on your compiled wasm
-    Init { path: Option<String> },
+    Init {
+        path: Option<String>,
+        #[structopt(long = "scope", short = "s")]
+        scope: Option<String>,
+    },
     #[structopt(name = "pack")]
     /// 🍱  create a tar of your npm package but don't publish! [NOT IMPLEMENTED]
     Pack {},
@@ -34,7 +38,7 @@ enum Command {
 }
 
 main!(|args: Cli, log_level: verbosity| match args.cmd {
-    Command::Init { path } => {
+    Command::Init { path, scope } => {
         let started = Instant::now();
 
         let crate_path = match path {
@@ -45,7 +49,7 @@ main!(|args: Cli, log_level: verbosity| match args.cmd {
         build::rustup_add_wasm_target();
         build::cargo_build_wasm(&crate_path);
         wasm_pack::create_pkg_dir(&crate_path)?;
-        manifest::write_package_json(&crate_path)?;
+        manifest::write_package_json(&crate_path, scope)?;
         readme::copy_from_crate(&crate_path)?;
         bindgen::cargo_install_wasm_bindgen();
         let name = manifest::get_crate_name(&crate_path)?;

src/manifest.rs

@@ -49,10 +49,13 @@ fn read_cargo_toml(path: &str) -> Result<CargoManifest, Error> {
 }
 
 impl CargoManifest {
-    fn into_npm(self) -> NpmPackage {
+    fn into_npm(mut self, scope: Option<String>) -> NpmPackage {
         let filename = self.package.name.replace("-", "_");
         let js_file = format!("{}.js", filename);
         let wasm_file = format!("{}_bg.wasm", filename);
+        if let Some(s) = scope {
+            self.package.name = format!("@{}/{}", s, self.package.name);
+        }
         NpmPackage {
             name: self.package.name,
             description: self.package.description,
@@ -68,7 +71,7 @@ impl CargoManifest {
 }
 
 /// Generate a package.json file inside in `./pkg`.
-pub fn write_package_json(path: &str) -> Result<(), Error> {
+pub fn write_package_json(path: &str, scope: Option<String>) -> Result<(), Error> {
     let step = format!(
         "{} {}Writing a package.json...",
         style("[4/7]").bold().dim(),
@@ -78,7 +81,7 @@ pub fn write_package_json(path: &str) -> Result<(), Error> {
     let pkg_file_path = format!("{}/pkg/package.json", path);
     let mut pkg_file = File::create(pkg_file_path)?;
     let crate_data = read_cargo_toml(path)?;
-    let npm_data = crate_data.into_npm();
+    let npm_data = crate_data.into_npm(scope);
     let npm_json = serde_json::to_string(&npm_data)?;
     pkg_file.write_all(npm_json.as_bytes())?;
     pb.finish();

tests/fixtures/scopes/Cargo.lock

@@ -0,0 +1,140 @@
+[[package]]
+name = "dtoa"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "fnv"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "itoa"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "num-traits"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "proc-macro2"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "quote"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "scopes-hello-world"
+version = "0.1.0"
+dependencies = [
+ "wasm-bindgen 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "serde"
+version = "1.0.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "serde_derive"
+version = "1.0.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive_internals 0.20.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.12.14 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "serde_derive_internals"
+version = "0.20.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.12.14 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "dtoa 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itoa 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "syn"
+version = "0.12.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "unicode-xid"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "wasm-bindgen"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "wasm-bindgen-macro 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.12.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasm-bindgen-shared 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[metadata]
+"checksum dtoa 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "09c3753c3db574d215cba4ea76018483895d7bff25a31b49ba45db21c48e50ab"
+"checksum fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "2fad85553e09a6f881f739c29f0b00b0f01357c743266d478b68951ce23285f3"
+"checksum itoa 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8324a32baf01e2ae060e9de58ed0bc2320c9a2833491ee36cd3b4c414de4db8c"
+"checksum num-traits 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "0b3c2bd9b9d21e48e956b763c9f37134dc62d9e95da6edb3f672cacb6caf3cd3"
+"checksum proc-macro2 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "cd07deb3c6d1d9ff827999c7f9b04cdfd66b1b17ae508e14fe47b620f2282ae0"
+"checksum quote 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "1eca14c727ad12702eb4b6bfb5a232287dcf8385cb8ca83a3eeaf6519c44c408"
+"checksum serde 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)" = "c73f63e08b33f6e59dfb3365b009897ebc3a3edc4af6e4f3ce8e483cf3d80ce7"
+"checksum serde_derive 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)" = "9cd9e89b8be5b611971734eaf887f1da0ce1a5b51491f04b09fe855649a84f3b"
+"checksum serde_derive_internals 0.20.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a79b781fe5c4a7037a10a485249a499ea02927046360afe7e04885aad2f9c10c"
+"checksum serde_json 1.0.11 (registry+https://github.com/rust-lang/crates.io-index)" = "fab6c4d75bedcf880711c85e39ebf8ccc70d0eba259899047ec5d7436643ee17"
+"checksum syn 0.12.14 (registry+https://github.com/rust-lang/crates.io-index)" = "8c5bc2d6ff27891209efa5f63e9de78648d7801f085e4653701a692ce938d6fd"
+"checksum unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
+"checksum wasm-bindgen 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "717507a3c7ef09d740c6d781bda57ba054d7b776f3e27d4478e25a773afd2e4b"
+"checksum wasm-bindgen-macro 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cbc1a194a8fe6319f9f326f0c03d2083d61727ace574f9b1df083bad79a314ad"
+"checksum wasm-bindgen-shared 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "8b7cf730a826f1ec1ea2143d8582d5d2d27c0775035652daf0e0337225e8566b"

tests/fixtures/scopes/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "scopes-hello-world"
+description = "an example rust->wasm crate"
+version = "0.1.0"
+authors = ["Michael Gattozzi <mgattozzi@gmail.com>"]
+license = "WTFPL"
+repository = "https://github.com/ashleygwilliams/wasm-pack"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+wasm-bindgen = "0.1.0"

tests/fixtures/scopes/README.md

@@ -0,0 +1,2 @@
+# scopes-hello-world
+> an example rust -> wasm project

tests/fixtures/scopes/src/lib.rs

@@ -0,0 +1,15 @@
+#![feature(proc_macro)]
+
+extern crate wasm_bindgen;
+
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+extern {
+    fn alert(s: &str);
+}
+
+#[wasm_bindgen]
+pub fn greet(name: &str) {
+    alert(&format!("Hello, {}!", name));
+}

tests/manifest/main.rs

@@ -29,7 +29,7 @@ fn it_gets_the_crate_name_provided_path() {
 fn it_creates_a_package_json_default_path() {
     let path = ".".to_string();
     wasm_pack::create_pkg_dir(&path).unwrap();
-    assert!(manifest::write_package_json(&path).is_ok());
+    assert!(manifest::write_package_json(&path, None).is_ok());
     let package_json_path = format!("{}/pkg/package.json", &path);
     assert!(fs::metadata(package_json_path).is_ok());
     assert!(utils::read_package_json(&path).is_ok());
@@ -47,7 +47,7 @@ fn it_creates_a_package_json_default_path() {
 fn it_creates_a_package_json_provided_path() {
     let path = "tests/fixtures/js-hello-world".to_string();
     wasm_pack::create_pkg_dir(&path).unwrap();
-    assert!(manifest::write_package_json(&path).is_ok());
+    assert!(manifest::write_package_json(&path, None).is_ok());
     let package_json_path = format!("{}/pkg/package.json", &path);
     assert!(fs::metadata(package_json_path).is_ok());
     assert!(utils::read_package_json(&path).is_ok());
@@ -55,3 +55,19 @@ fn it_creates_a_package_json_provided_path() {
     assert_eq!(pkg.name, "js-hello-world");
     assert_eq!(pkg.files, ["js_hello_world.js", "js_hello_world_bg.wasm"]);
 }
+
+#[test]
+fn it_creates_a_package_json_provided_path_with_scope() {
+    let path = "tests/fixtures/scopes".to_string();
+    wasm_pack::create_pkg_dir(&path).unwrap();
+    assert!(manifest::write_package_json(&path, Some("test".to_string())).is_ok());
+    let package_json_path = format!("{}/pkg/package.json", &path);
+    assert!(fs::metadata(package_json_path).is_ok());
+    assert!(utils::read_package_json(&path).is_ok());
+    let pkg = utils::read_package_json(&path).unwrap();
+    assert_eq!(pkg.name, "@test/scopes-hello-world");
+    assert_eq!(
+        pkg.files,
+        ["scopes_hello_world.js", "scopes_hello_world_bg.wasm"]
+    );
+}