update fetch to take a string parameter

crates/cli-support/src/wasm2es6js.rs

@@ -1,7 +1,6 @@
 extern crate base64;
 
 use std::collections::HashSet;
-use std::path::PathBuf;
 
 use parity_wasm::elements::*;
 
@@ -9,23 +8,20 @@ use super::Error;
 
 pub struct Config {
     base64: bool,
-    fetch: bool,
-    file_name: String,
+    fetch_path: Option<String>,
 }
 
 pub struct Output {
     module: Module,
     base64: bool,
-    fetch: bool,
-    file_name: String,
+    fetch_path: Option<String>,
 }
 
 impl Config {
     pub fn new() -> Config {
         Config {
             base64: false,
-            fetch: false,
-            file_name: String::new(),
+            fetch_path: None,
         }
     }
 
@@ -34,18 +30,14 @@ impl Config {
         self
     }
     
-    pub fn fetch(&mut self, fetch: bool, in_path: &PathBuf) -> &mut Self {
-        self.fetch = fetch;
-        self.file_name = match in_path.file_name() {
-            Some(os_str) => os_str.to_str().unwrap_or("").to_string(),
-            None => String::new()
-        };
+    pub fn fetch(&mut self, path: Option<String>) -> &mut Self {
+        self.fetch_path = path;
         self
     }
 
     pub fn generate(&mut self, wasm: &[u8]) -> Result<Output, Error> {
-        if !self.base64 && !self.fetch {
-            panic!()
+        if !self.base64 && !self.fetch_path.is_some() {
+            panic!("the option --base64 or --fetch is required");
         }
         let module = deserialize_buffer(wasm).map_err(|e| {
             ::Error(format!("{:?}", e))
@@ -53,8 +45,7 @@ impl Config {
         Ok(Output {
             module,
             base64: self.base64,
-            fetch: self.fetch,
-            file_name: self.file_name.clone(),
+            fetch_path: self.fetch_path.clone(),
         })
     }
 }
@@ -222,12 +213,12 @@ impl Output {
                     }}", base64 = base64::encode(&wasm)),
                 inst
             )
-        } else if self.fetch {
+        } else if self.fetch_path.is_some() {
             (
                 String::new(),
-                format!("fetch('/{name}')
+                format!("fetch('{path}')
                 .then(res => res.arrayBuffer())
-                .then(bytes => {inst})", name = self.file_name, inst = inst)
+                .then(bytes => {inst})", path = self.fetch_path.unwrap(), inst = inst)
             )
         } else {
             panic!("the option --base64 or --fetch is required");

crates/cli/src/bin/wasm2es6js.rs

@@ -22,7 +22,7 @@ Options:
     -o --output FILE        File to place output in
     --typescript            Output a `*.d.ts` file next to the JS output
     --base64                Inline the wasm module using base64 encoding
-    --fetch                 Load module via `fetch()` instead of default webpack implementation
+    --fetch PATH            Load module by passing the PATH argument to `fetch()`
 
 Note that this is not intended to produce a production-ready output module
 but rather is intended purely as a temporary \"hack\" until it's standard in
@@ -34,7 +34,7 @@ struct Args {
     flag_output: Option<PathBuf>,
     flag_typescript: bool,
     flag_base64: bool,
-    flag_fetch: bool,
+    flag_fetch: Option<String>,
     arg_input: PathBuf,
 }
 
@@ -43,7 +43,7 @@ fn main() {
         .and_then(|d| d.deserialize())
         .unwrap_or_else(|e| e.exit());
 
-    if !args.flag_base64 && !args.flag_fetch {
+    if !args.flag_base64 && !args.flag_fetch.is_some() {
         panic!("unfortunately only works right now with base64 or fetch");
     }
 
@@ -53,7 +53,7 @@ fn main() {
 
     let object = wasm_bindgen_cli_support::wasm2es6js::Config::new()
         .base64(args.flag_base64)
-        .fetch(args.flag_fetch, &args.arg_input)
+        .fetch(args.flag_fetch)
         .generate(&wasm)
         .expect("failed to parse wasm");
 

examples/hello_world/chrome/build_fetch.sh

@@ -8,14 +8,13 @@ cargo +nightly run -p wasm-bindgen-cli --bin wasm-bindgen -- \
   ../../../target/wasm32-unknown-unknown/debug/hello_world.wasm --out-dir .
 
 # To avoid a bug occurring when webpack, wasm, and Chrome are used together, we
-# convert the .wasm module to a .js module that embeds the wasm bytecode. To
-# enable this, use the "--resolve-enxensions .js" flag when starting 
-# webpack-dev-server
+# create a .js module that will download the .wasm module via fetch. 
 cargo +nightly run -p wasm-bindgen-cli --bin wasm2es6js -- \
-  --fetch -o hello_world_bg.js hello_world_bg.wasm
-# wasm2es6js --base64 -o hello_world_bg.js hello_world_bg.wasm
+  --fetch ./hello_world_bg.wasm -o hello_world_bg.js hello_world_bg.wasm
 
 # And like the directory above this, from here it's the same.
 npm install
-#force webpack-dev-server to ignore the .wasm file
+
+# since we kept the same name for the .js module, we need
+# to force webpack to ignore any other file extensions
 npm run serve -- --resolve-extensions .js