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use std::{collections::HashMap, env, sync::Arc};
use anyhow::{bail, Context, Error};
use helpers::Helpers;
use rustc_hash::FxHashMap;
use swc::{
config::{GlobalInliningPassEnvs, InputSourceMap, IsModule, JscConfig, TransformConfig},
try_with_handler,
};
use swc_atoms::Atom;
use swc_bundler::{Load, ModuleData};
use swc_common::{
comments::{NoopComments, SingleThreadedComments},
errors::{Handler, HANDLER},
sync::Lrc,
FileName, Mark, DUMMY_SP,
};
use swc_ecma_ast::{noop_pass, EsVersion, Expr, Lit, Module, Program, Str};
use swc_ecma_parser::{parse_file_as_module, Syntax};
use swc_ecma_transforms::{
helpers,
optimization::{
inline_globals,
simplify::{dead_branch_remover, expr_simplifier},
},
react::jsx,
resolver,
typescript::typescript,
};
use crate::loaders::json::load_json_as_module;
/// JavaScript loader
pub struct SwcLoader {
compiler: Arc<swc::Compiler>,
options: swc::config::Options,
}
impl SwcLoader {
pub fn new(compiler: Arc<swc::Compiler>, options: swc::config::Options) -> Self {
SwcLoader { compiler, options }
}
fn env_map(&self) -> Lrc<FxHashMap<Atom, Expr>> {
let mut m = HashMap::default();
let envs = self
.options
.config
.jsc
.transform
.as_ref()
.and_then(|t| t.optimizer.as_ref())
.and_then(|o| o.globals.as_ref())
.map(|g| g.envs.clone())
.unwrap_or_default();
let envs_map: FxHashMap<_, _> = match envs {
GlobalInliningPassEnvs::Map(m) => m,
GlobalInliningPassEnvs::List(envs) => envs
.into_iter()
.map(|name| {
let value = env::var(&name).ok();
(name.into(), value.unwrap_or_default().into())
})
.collect(),
};
for (k, v) in envs_map {
m.insert(
k,
Lit::Str(Str {
span: DUMMY_SP,
raw: None,
value: v.into(),
})
.into(),
);
}
Lrc::new(m)
}
fn load_with_handler(&self, handler: &Handler, name: &FileName) -> Result<ModuleData, Error> {
tracing::debug!("JsLoader.load({})", name);
let helpers = Helpers::new(false);
if let FileName::Custom(id) = name {
// Handle built-in modules
if id.starts_with("node:") {
let fm = self
.compiler
.cm
.new_source_file(name.clone().into(), "".to_string());
return Ok(ModuleData {
fm,
module: Module {
span: DUMMY_SP,
body: Default::default(),
shebang: Default::default(),
},
helpers: Default::default(),
});
// Handle disabled modules, eg when `browser` has a field
// set to `false`
} else {
// TODO: When we know the calling context is ESM
// TODO: switch to `export default {}`.
let fm = self
.compiler
.cm
.new_source_file(name.clone().into(), "module.exports = {}".to_string());
let module = parse_file_as_module(
&fm,
Syntax::Es(Default::default()),
Default::default(),
None,
&mut Vec::new(),
)
.unwrap();
return Ok(ModuleData {
fm,
module,
helpers: Default::default(),
});
}
}
let fm = self
.compiler
.cm
.load_file(match name {
FileName::Real(v) => v,
_ => bail!("swc-loader only accepts path. Got `{name}`"),
})
.with_context(|| format!("failed to load file `{name}`"))?;
if let FileName::Real(path) = name {
if let Some(ext) = path.extension() {
if ext == "json" {
let module = load_json_as_module(&fm)
.with_context(|| format!("failed to load json file at {}", fm.name))?;
return Ok(ModuleData {
fm,
module,
helpers: Default::default(),
});
}
}
}
tracing::trace!("JsLoader.load: loaded");
let program = if fm.name.to_string().contains("node_modules") {
let comments = self.compiler.comments().clone();
let mut program = self.compiler.parse_js(
fm.clone(),
handler,
EsVersion::Es2020,
Default::default(),
IsModule::Bool(true),
Some(&comments),
)?;
helpers::HELPERS.set(&helpers, || {
HANDLER.set(handler, || {
let unresolved_mark = Mark::new();
let top_level_mark = Mark::new();
program.mutate(&mut resolver(unresolved_mark, top_level_mark, false));
program.mutate(&mut typescript(
Default::default(),
unresolved_mark,
top_level_mark,
));
program.mutate(&mut jsx(
self.compiler.cm.clone(),
None::<NoopComments>,
Default::default(),
top_level_mark,
unresolved_mark,
));
program.mutate(&mut inline_globals(
self.env_map(),
Default::default(),
Default::default(),
Default::default(),
));
program.mutate(&mut expr_simplifier(unresolved_mark, Default::default()));
program.mutate(&mut dead_branch_remover(unresolved_mark));
program
})
})
} else {
let comments = SingleThreadedComments::default();
let config = self.compiler.parse_js_as_input(
fm.clone(),
None,
handler,
&swc::config::Options {
config: {
let c = &self.options.config;
swc::config::Config {
jsc: JscConfig {
transform: {
c.jsc
.transform
.as_ref()
.map(|c| TransformConfig {
react: c.react.clone(),
const_modules: c.const_modules.clone(),
optimizer: None,
legacy_decorator: c.legacy_decorator,
decorator_metadata: c.decorator_metadata,
hidden: Default::default(),
..Default::default()
})
.into()
},
external_helpers: true.into(),
..c.jsc.clone()
},
module: None,
minify: false.into(),
input_source_map: InputSourceMap::Bool(false).into(),
..c.clone()
}
},
skip_helper_injection: true,
disable_hygiene: false,
disable_fixer: true,
top_level_mark: self.options.top_level_mark,
cwd: self.options.cwd.clone(),
caller: None,
filename: String::new(),
config_file: None,
root: None,
swcrc: true,
env_name: { env::var("NODE_ENV").unwrap_or_else(|_| "development".into()) },
..Default::default()
},
&fm.name,
Some(&comments),
|_| noop_pass(),
)?;
tracing::trace!("JsLoader.load: loaded config");
// We run transform at this phase to strip out unused dependencies.
//
// Note that we don't apply compat transform at loading phase.
let program = if let Some(config) = config {
let mut program = config.program;
let pass = config.pass;
helpers::HELPERS.set(&helpers, || {
HANDLER.set(handler, || {
let unresolved_mark = Mark::new();
let top_level_mark = Mark::new();
program.mutate(&mut resolver(unresolved_mark, top_level_mark, false));
program.mutate(&mut typescript(
Default::default(),
unresolved_mark,
top_level_mark,
));
program.mutate(&mut jsx(
self.compiler.cm.clone(),
None::<NoopComments>,
Default::default(),
top_level_mark,
unresolved_mark,
));
program.mutate(&mut inline_globals(
self.env_map(),
Default::default(),
Default::default(),
Default::default(),
));
program.mutate(&mut expr_simplifier(unresolved_mark, Default::default()));
program.mutate(&mut dead_branch_remover(unresolved_mark));
program.apply(pass)
})
})
} else {
let comments = self.compiler.comments().clone();
self.compiler
.parse_js(
fm.clone(),
handler,
EsVersion::Es2020,
config.as_ref().map(|v| v.syntax).unwrap_or_default(),
IsModule::Bool(true),
Some(&comments),
)
.context("tried to parse as ecmascript as it's excluded by .swcrc")?
};
tracing::trace!("JsLoader.load: applied transforms");
program
};
match program {
Program::Module(module) => Ok(ModuleData {
fm,
module,
helpers,
}),
_ => unreachable!(),
}
}
}
impl Load for SwcLoader {
fn load(&self, name: &FileName) -> Result<ModuleData, Error> {
try_with_handler(self.compiler.cm.clone(), Default::default(), |handler| {
self.load_with_handler(handler, name)
})
.map_err(|e| e.to_pretty_error())
}
}