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//! package.json definitions
//!
//! Code related to export field are copied from [Parcel's resolver](https://github.com/parcel-bundler/parcel/blob/v2/packages/utils/node-resolver-rs/src/package_json.rs)
use std::path::{Path, PathBuf};
use serde_json::Value as JSONValue;
use crate::{path::PathUtil, ResolveError};
pub type JSONMap = serde_json::Map<String, JSONValue>;
/// Deserialized package.json
#[derive(Debug, Default)]
pub struct PackageJson {
/// Path to `package.json`. Contains the `package.json` filename.
pub path: PathBuf,
/// Realpath to `package.json`. Contains the `package.json` filename.
pub realpath: PathBuf,
/// The "name" field defines your package's name.
/// The "name" field can be used in addition to the "exports" field to self-reference a package using its name.
///
/// <https://nodejs.org/api/packages.html#name>
pub name: Option<String>,
/// The "type" field.
///
/// <https://nodejs.org/api/packages.html#type>
pub r#type: Option<JSONValue>,
/// The "sideEffects" field.
///
/// <https://webpack.js.org/guides/tree-shaking>
pub side_effects: Option<JSONValue>,
raw_json: std::sync::Arc<JSONValue>,
}
impl PackageJson {
/// # Panics
/// # Errors
pub(crate) fn parse(
path: PathBuf,
realpath: PathBuf,
json: &str,
) -> Result<Self, serde_json::Error> {
let mut raw_json: JSONValue = serde_json::from_str(json)?;
let mut package_json = Self::default();
if let Some(json_object) = raw_json.as_object_mut() {
// Remove large fields that are useless for pragmatic use.
#[cfg(feature = "package_json_raw_json_api")]
{
json_object.remove("description");
json_object.remove("keywords");
json_object.remove("scripts");
json_object.remove("dependencies");
json_object.remove("devDependencies");
json_object.remove("peerDependencies");
json_object.remove("optionalDependencies");
}
// Add name, type and sideEffects.
package_json.name =
json_object.get("name").and_then(|field| field.as_str()).map(ToString::to_string);
package_json.r#type = json_object.get("type").cloned();
package_json.side_effects = json_object.get("sideEffects").cloned();
}
package_json.path = path;
package_json.realpath = realpath;
package_json.raw_json = std::sync::Arc::new(raw_json);
Ok(package_json)
}
fn get_value_by_path<'a>(
fields: &'a serde_json::Map<String, JSONValue>,
path: &[String],
) -> Option<&'a JSONValue> {
if path.is_empty() {
return None;
}
let mut value = fields.get(&path[0])?;
for key in path.iter().skip(1) {
if let Some(inner_value) = value.as_object().and_then(|o| o.get(key)) {
value = inner_value;
} else {
return None;
}
}
Some(value)
}
/// Raw serde json value of `package.json`.
///
/// This is currently used in Rspack for:
/// * getting the `sideEffects` field
/// * query in <https://www.rspack.dev/config/module.html#ruledescriptiondata> - search on GitHub indicates query on the `type` field.
///
/// To reduce overall memory consumption, large fields that useless for pragmatic use are removed.
/// They are: `description`, `keywords`, `scripts`,
/// `dependencies` and `devDependencies`, `peerDependencies`, `optionalDependencies`.
#[cfg(feature = "package_json_raw_json_api")]
pub fn raw_json(&self) -> &std::sync::Arc<JSONValue> {
&self.raw_json
}
/// Directory to `package.json`
///
/// # Panics
///
/// * When the package.json path is misconfigured.
pub fn directory(&self) -> &Path {
debug_assert!(self.realpath.file_name().is_some_and(|x| x == "package.json"));
self.realpath.parent().unwrap()
}
/// The "main" field defines the entry point of a package when imported by name via a node_modules lookup. Its value is a path.
///
/// When a package has an "exports" field, this will take precedence over the "main" field when importing the package by name.
///
/// Values are dynamically retrieved from [ResolveOptions::main_fields].
///
/// <https://nodejs.org/api/packages.html#main>
pub(crate) fn main_fields<'a>(
&'a self,
main_fields: &'a [String],
) -> impl Iterator<Item = &'a str> + '_ {
main_fields
.iter()
.filter_map(|main_field| self.raw_json.get(main_field))
.filter_map(|value| value.as_str())
}
/// The "exports" field allows defining the entry points of a package when imported by name loaded either via a node_modules lookup or a self-reference to its own name.
///
/// <https://nodejs.org/api/packages.html#exports>
pub(crate) fn exports_fields<'a>(
&'a self,
exports_fields: &'a [Vec<String>],
) -> impl Iterator<Item = &'a JSONValue> + '_ {
exports_fields.iter().filter_map(|object_path| {
self.raw_json
.as_object()
.and_then(|json_object| Self::get_value_by_path(json_object, object_path))
})
}
/// In addition to the "exports" field, there is a package "imports" field to create private mappings that only apply to import specifiers from within the package itself.
///
/// <https://nodejs.org/api/packages.html#subpath-imports>
pub(crate) fn imports_fields<'a>(
&'a self,
imports_fields: &'a [Vec<String>],
) -> impl Iterator<Item = &'a JSONMap> + '_ {
imports_fields.iter().filter_map(|object_path| {
self.raw_json
.as_object()
.and_then(|json_object| Self::get_value_by_path(json_object, object_path))
.and_then(|value| value.as_object())
})
}
/// The "browser" field is provided by a module author as a hint to javascript bundlers or component tools when packaging modules for client side use.
/// Multiple values are configured by [ResolveOptions::alias_fields].
///
/// <https://github.com/defunctzombie/package-browser-field-spec>
fn browser_fields<'a>(
&'a self,
alias_fields: &'a [Vec<String>],
) -> impl Iterator<Item = &'a JSONMap> + '_ {
alias_fields.iter().filter_map(|object_path| {
self.raw_json
.as_object()
.and_then(|json_object| Self::get_value_by_path(json_object, object_path))
// Only object is valid, all other types are invalid
// https://github.com/webpack/enhanced-resolve/blob/3a28f47788de794d9da4d1702a3a583d8422cd48/lib/AliasFieldPlugin.js#L44-L52
.and_then(|value| value.as_object())
})
}
/// Resolve the request string for this package.json by looking at the `browser` field.
///
/// # Errors
///
/// * Returns [ResolveError::Ignored] for `"path": false` in `browser` field.
pub(crate) fn resolve_browser_field<'a>(
&'a self,
path: &Path,
request: Option<&str>,
alias_fields: &'a [Vec<String>],
) -> Result<Option<&str>, ResolveError> {
for object in self.browser_fields(alias_fields) {
if let Some(request) = request {
if let Some(value) = object.get(request) {
return Self::alias_value(path, value);
}
} else {
let dir = self.path.parent().unwrap();
for (key, value) in object {
let joined = dir.normalize_with(key);
if joined == path {
return Self::alias_value(path, value);
}
}
}
}
Ok(None)
}
fn alias_value<'a>(key: &Path, value: &'a JSONValue) -> Result<Option<&'a str>, ResolveError> {
match value {
JSONValue::String(value) => Ok(Some(value.as_str())),
JSONValue::Bool(b) if !b => Err(ResolveError::Ignored(key.to_path_buf())),
_ => Ok(None),
}
}
}