Add support for `--target web`

This commit adds support for the new `--web` flag in `wasm-bindgen`
under the flag name `--target web`. To ensure that it was plubmed around
the stringly-typed `target` type was switched to an `enum Target` to
ensure that all cases it's looked at are handled appropriately for the
new `web` target.

docs/src/commands/build.md

@@ -47,20 +47,26 @@ The exact meaning of the profile flags may evolve as the platform matures.
 
 ## Target
 
-The `build` command accepts a `--target` argument. This will customize the output files
-to align with a particular type of JS module. This allows wasm-pack to generate either
-ES6 modules or CommonJS modules for use in browser and in NodeJS. Defaults to `browser`.
-The options are:
+The `build` command accepts a `--target` argument. This will customize the JS
+that is emitted and how the WebAssembly files are instantiated and loaded. For
+more documentation on the various strategies here, see the [documentation on
+using the compiled output][deploy].
 
 ```
 wasm-pack build --target nodejs
 ```
 
-| Option    | Description                                                                                                     |
-|-----------|-----------------------------------------------------------------------------------------------------------------|
-| `nodejs`  | Outputs JS that uses CommonJS modules, for use with a `require` statement. `main` key in `package.json`. |
-| `no-modules`  | Outputs JS that use no modules. `browser` key in `package.json`. |
-| `browser` | Outputs JS that uses ES6 modules, primarily for use with `import` statements and/or bundlers such as `webpack`. `module` key in `package.json`. `sideEffects: false` by default. |
+| Option    | Usage | Description                                                                                                     |
+|-----------|------------|-----------------------------------------------------------------------------------------------------|
+| *not specified* or `bundler` | [Bundler][bundlers] | Outputs JS that is suitable for interoperation with a Bundler like Webpack. You'll `import` the JS and the `module` key is specified in `package.json`. `sideEffects: false` is by default. |
+| `nodejs`  | [Node.js][deploy-nodejs] | Outputs JS that uses CommonJS modules, for use with a `require` statement. `main` key in `package.json`. |
+| `web` | [Native in browser][deploy-web] | Outputs JS that can be natively imported as an ES module in a browser, but the WebAssembly must be manually instantiated and loaded. |
+| `no-modules` | [Native in browser][deploy-web] | Same as `web`, except the JS is included on a page and modifies global state, and doesn't support as many `wasm-bindgen` features as `web` |
+
+[deploy]: https://rustwasm.github.io/docs/wasm-bindgen/reference/deployment.html
+[bundlers]: https://rustwasm.github.io/docs/wasm-bindgen/reference/deployment.html#bundlers
+[deploy-nodejs]: https://rustwasm.github.io/docs/wasm-bindgen/reference/deployment.html#nodejs
+[deploy-web]: https://rustwasm.github.io/docs/wasm-bindgen/reference/deployment.html#without-a-bundler
 
 ## Scope
 

src/bindgen.rs

@@ -2,7 +2,7 @@
 
 use binary_install::{Cache, Download};
 use child;
-use command::build::BuildProfile;
+use command::build::{BuildProfile, Target};
 use emoji;
 use failure::{self, ResultExt};
 use log::debug;
@@ -176,7 +176,7 @@ pub fn wasm_bindgen_build(
     bindgen: &Download,
     out_dir: &Path,
     disable_dts: bool,
-    target: &str,
+    target: &Target,
     profile: BuildProfile,
     step: &Step,
 ) -> Result<(), failure::Error> {
@@ -203,9 +203,10 @@ pub fn wasm_bindgen_build(
         "--typescript"
     };
     let target_arg = match target {
-        "nodejs" => "--nodejs",
-        "no-modules" => "--no-modules",
-        _ => "--browser",
+        Target::Nodejs => "--nodejs",
+        Target::NoModules => "--no-modules",
+        Target::Web => "--web",
+        Target::Bundler => "--browser",
     };
     let bindgen_path = bindgen.binary("wasm-bindgen")?;
     let mut cmd = Command::new(bindgen_path);

src/command/build.rs

@@ -26,7 +26,7 @@ pub struct Build {
     pub crate_data: manifest::CrateData,
     pub scope: Option<String>,
     pub disable_dts: bool,
-    pub target: String,
+    pub target: Target,
     pub profile: BuildProfile,
     pub mode: BuildMode,
     pub out_dir: PathBuf,
@@ -66,6 +66,44 @@ impl FromStr for BuildMode {
     }
 }
 
+/// What sort of output we're going to be generating and flags we're invoking
+/// `wasm-bindgen` with.
+#[derive(Clone, Copy, Debug)]
+pub enum Target {
+    /// Default output mode or `--target bundler`, indicates output will be
+    /// used with a bundle in a later step.
+    Bundler,
+    /// Correspond to `--target web` where the output is natively usable as an
+    /// ES module in a browser and the wasm is manually instantiated.
+    Web,
+    /// Correspond to `--target nodejs` where the output is natively usable as
+    /// a Node.js module loaded with `require`.
+    Nodejs,
+    /// Correspond to `--target no-modules` where the output is natively usable
+    /// in a browser but pollutes the global namespace and must be manually
+    /// instantiated.
+    NoModules,
+}
+
+impl Default for Target {
+    fn default() -> Target {
+        Target::Bundler
+    }
+}
+
+impl FromStr for Target {
+    type Err = Error;
+    fn from_str(s: &str) -> Result<Self, Error> {
+        match s {
+            "bundler" | "browser" => Ok(Target::Bundler),
+            "web" => Ok(Target::Web),
+            "nodejs" => Ok(Target::Nodejs),
+            "no-modules" => Ok(Target::NoModules),
+            _ => bail!("Unknown target: {}", s),
+        }
+    }
+}
+
 /// The build profile controls whether optimizations, debug info, and assertions
 /// are enabled or disabled.
 #[derive(Clone, Copy, Debug)]
@@ -99,8 +137,8 @@ pub struct BuildOptions {
     pub disable_dts: bool,
 
     #[structopt(long = "target", short = "t", default_value = "browser")]
-    /// Sets the target environment. [possible values: browser, nodejs, no-modules]
-    pub target: String,
+    /// Sets the target environment. [possible values: browser, nodejs, web, no-modules]
+    pub target: Target,
 
     #[structopt(long = "debug")]
     /// Deprecated. Renamed to `--dev`.
@@ -133,9 +171,9 @@ impl Default for BuildOptions {
         Self {
             path: None,
             scope: None,
-            mode: BuildMode::Normal,
+            mode: BuildMode::default(),
             disable_dts: false,
-            target: String::new(),
+            target: Target::default(),
             debug: false,
             dev: false,
             release: false,
@@ -165,12 +203,6 @@ impl Build {
             _ => bail!("Can only supply one of the --dev, --release, or --profiling flags"),
         };
 
-        // `possible_values` in clap isn't supported by `structopt`
-        let possible_targets = ["browser", "nodejs", "no-modules"];
-        if !possible_targets.contains(&build_opts.target.as_str()) {
-            bail!("Supported targets: browser, nodejs, no-modules");
-        }
-
         Ok(Build {
             crate_path,
             crate_data,

src/command/publish/mod.rs

@@ -2,7 +2,7 @@
 pub mod access;
 
 use self::access::Access;
-use command::build::{Build, BuildOptions};
+use command::build::{Build, BuildOptions, Target};
 use command::utils::{find_pkg_directory, set_crate_path};
 use dialoguer::{Confirmation, Input, Select};
 use failure::Error;
@@ -10,6 +10,7 @@ use log::info;
 use npm;
 use std::path::PathBuf;
 use std::result;
+use std::str::FromStr;
 use PBAR;
 
 /// Creates a tarball from a 'pkg' directory
@@ -45,6 +46,7 @@ pub fn publish(
                     .default(0)
                     .interact()?
                     .to_string();
+                let target = Target::from_str(&target)?;
                 let build_opts = BuildOptions {
                     path: Some(crate_path.clone()),
                     target,

src/manifest/mod.rs

@@ -11,7 +11,7 @@ use self::npm::{
     repository::Repository, CommonJSPackage, ESModulesPackage, NoModulesPackage, NpmPackage,
 };
 use cargo_metadata::Metadata;
-use command::build::BuildProfile;
+use command::build::{BuildProfile, Target};
 use emoji;
 use failure::{Error, ResultExt};
 use progressbar::Step;
@@ -377,19 +377,18 @@ impl CrateData {
         out_dir: &Path,
         scope: &Option<String>,
         disable_dts: bool,
-        target: &str,
+        target: &Target,
         step: &Step,
     ) -> Result<(), Error> {
         let msg = format!("{}Writing a package.json...", emoji::MEMO);
 
         PBAR.step(step, &msg);
         let pkg_file_path = out_dir.join("package.json");
-        let npm_data = if target == "nodejs" {
-            self.to_commonjs(scope, disable_dts, out_dir)
-        } else if target == "no-modules" {
-            self.to_nomodules(scope, disable_dts, out_dir)
-        } else {
-            self.to_esmodules(scope, disable_dts, out_dir)
+        let npm_data = match target {
+            Target::Nodejs => self.to_commonjs(scope, disable_dts, out_dir),
+            Target::NoModules => self.to_nomodules(scope, disable_dts, out_dir),
+            Target::Bundler => self.to_esmodules(scope, disable_dts, out_dir),
+            Target::Web => self.to_web(scope, disable_dts, out_dir),
         };
 
         let npm_json = serde_json::to_string_pretty(&npm_data)?;
@@ -522,6 +521,35 @@ impl CrateData {
         })
     }
 
+    fn to_web(&self, scope: &Option<String>, disable_dts: bool, out_dir: &Path) -> NpmPackage {
+        let data = self.npm_data(scope, false, disable_dts, out_dir);
+        let pkg = &self.data.packages[self.current_idx];
+
+        self.check_optional_fields();
+
+        NpmPackage::ESModulesPackage(ESModulesPackage {
+            name: data.name,
+            collaborators: pkg.authors.clone(),
+            description: self.manifest.package.description.clone(),
+            version: pkg.version.clone(),
+            license: self.license(),
+            repository: self
+                .manifest
+                .package
+                .repository
+                .clone()
+                .map(|repo_url| Repository {
+                    ty: "git".to_string(),
+                    url: repo_url,
+                }),
+            files: data.files,
+            module: data.main,
+            homepage: data.homepage,
+            types: data.dts_file,
+            side_effects: "false".to_string(),
+        })
+    }
+
     fn to_nomodules(
         &self,
         scope: &Option<String>,

tests/all/manifest.rs

@@ -3,6 +3,7 @@ use std::collections::HashSet;
 use std::fs;
 use std::path::PathBuf;
 use utils::{self, fixture};
+use wasm_pack::command::build::Target;
 use wasm_pack::{self, license, manifest};
 
 #[test]
@@ -66,7 +67,7 @@ fn it_creates_a_package_json_default_path() {
     let step = wasm_pack::progressbar::Step::new(1);
     wasm_pack::command::utils::create_pkg_dir(&out_dir, &step).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, false, "", &step)
+        .write_package_json(&out_dir, &None, false, &Target::Bundler, &step)
         .is_ok());
     let package_json_path = &fixture.path.join("pkg").join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -102,7 +103,7 @@ fn it_creates_a_package_json_provided_path() {
     let step = wasm_pack::progressbar::Step::new(1);
     wasm_pack::command::utils::create_pkg_dir(&out_dir, &step).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, false, "", &step)
+        .write_package_json(&out_dir, &None, false, &Target::Bundler, &step)
         .is_ok());
     let package_json_path = &fixture.path.join("pkg").join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -131,7 +132,13 @@ fn it_creates_a_package_json_provided_path_with_scope() {
     let step = wasm_pack::progressbar::Step::new(1);
     wasm_pack::command::utils::create_pkg_dir(&out_dir, &step).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &Some("test".to_string()), false, "", &step)
+        .write_package_json(
+            &out_dir,
+            &Some("test".to_string()),
+            false,
+            &Target::Bundler,
+            &step
+        )
         .is_ok());
     let package_json_path = &fixture.path.join("pkg").join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -160,7 +167,7 @@ fn it_creates_a_pkg_json_with_correct_files_on_node() {
     let step = wasm_pack::progressbar::Step::new(1);
     wasm_pack::command::utils::create_pkg_dir(&out_dir, &step).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, false, "nodejs", &step)
+        .write_package_json(&out_dir, &None, false, &Target::Nodejs, &step)
         .is_ok());
     let package_json_path = &out_dir.join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -196,7 +203,7 @@ fn it_creates_a_pkg_json_with_correct_files_on_nomodules() {
     let step = wasm_pack::progressbar::Step::new(1);
     wasm_pack::command::utils::create_pkg_dir(&out_dir, &step).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, false, "no-modules", &step)
+        .write_package_json(&out_dir, &None, false, &Target::NoModules, &step)
         .is_ok());
     let package_json_path = &out_dir.join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -231,7 +238,7 @@ fn it_creates_a_pkg_json_in_out_dir() {
     let step = wasm_pack::progressbar::Step::new(1);
     wasm_pack::command::utils::create_pkg_dir(&out_dir, &step).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, false, "", &step)
+        .write_package_json(&out_dir, &None, false, &Target::Bundler, &step)
         .is_ok());
 
     let package_json_path = &fixture.path.join(&out_dir).join("package.json");
@@ -247,7 +254,7 @@ fn it_creates_a_package_json_with_correct_keys_when_types_are_skipped() {
     let step = wasm_pack::progressbar::Step::new(1);
     wasm_pack::command::utils::create_pkg_dir(&out_dir, &step).unwrap();
     assert!(crate_data
-        .write_package_json(&out_dir, &None, true, "", &step)
+        .write_package_json(&out_dir, &None, true, &Target::Bundler, &step)
         .is_ok());
     let package_json_path = &out_dir.join("package.json");
     fs::metadata(package_json_path).unwrap();
@@ -310,7 +317,7 @@ fn it_sets_homepage_field_if_available_in_cargo_toml() {
     let step = wasm_pack::progressbar::Step::new(2);
     wasm_pack::command::utils::create_pkg_dir(&out_dir, &step).unwrap();
     crate_data
-        .write_package_json(&out_dir, &None, true, "", &step)
+        .write_package_json(&out_dir, &None, true, &Target::Bundler, &step)
         .unwrap();
 
     let pkg = utils::manifest::read_package_json(&fixture.path, &out_dir).unwrap();
@@ -327,7 +334,7 @@ fn it_sets_homepage_field_if_available_in_cargo_toml() {
     let step = wasm_pack::progressbar::Step::new(2);
     wasm_pack::command::utils::create_pkg_dir(&out_dir, &step).unwrap();
     crate_data
-        .write_package_json(&out_dir, &None, true, "", &step)
+        .write_package_json(&out_dir, &None, true, &Target::Bundler, &step)
         .unwrap();
 
     let pkg = utils::manifest::read_package_json(&fixture.path, &out_dir).unwrap();
@@ -430,7 +437,7 @@ fn it_lists_license_files_in_files_field_of_package_json() {
     wasm_pack::command::utils::create_pkg_dir(&out_dir, &step).unwrap();
     license::copy_from_crate(&crate_data, &fixture.path, &out_dir, &step).unwrap();
     crate_data
-        .write_package_json(&out_dir, &None, false, "", &step)
+        .write_package_json(&out_dir, &None, false, &Target::Bundler, &step)
         .unwrap();
 
     let package_json_path = &fixture.path.join("pkg").join("package.json");