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/**
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
*
* @format
* @oncall react_native
*/
"use strict";
const fs = require("fs");
const path = require("path");
class Package {
constructor({ file }) {
this.path = path.resolve(file);
this._root = path.dirname(this.path);
this._content = null;
}
/**
* The `browser` field and replacement behavior is specified in
* https://github.com/defunctzombie/package-browser-field-spec.
*/
getMain(mainFields) {
const json = this.read();
let main;
for (const name of mainFields) {
if (typeof json[name] === "string") {
main = json[name];
break;
}
}
// flowlint-next-line sketchy-null-string:off
if (!main) {
main = "index";
}
const replacements = getReplacements(json, mainFields);
if (replacements) {
const variants = [main];
if (main.slice(0, 2) === "./") {
variants.push(main.slice(2));
} else {
variants.push("./" + main);
}
for (const variant of variants) {
const winner =
replacements[variant] ||
replacements[variant + ".js"] ||
replacements[variant + ".json"] ||
replacements[variant.replace(/(\.js|\.json)$/, "")];
if (winner) {
main = winner;
break;
}
}
}
return path.join(this._root, main);
}
invalidate() {
this._content = null;
}
redirectRequire(name, mainFields) {
const json = this.read();
const replacements = getReplacements(json, mainFields);
if (!replacements) {
return name;
}
if (!name.startsWith(".") && !path.isAbsolute(name)) {
const replacement = replacements[name];
// support exclude with "someDependency": false
return replacement === false ? false : replacement || name;
}
let relPath =
"./" + path.relative(this._root, path.resolve(this._root, name));
if (path.sep !== "/") {
relPath = relPath.replace(new RegExp("\\" + path.sep, "g"), "/");
}
let redirect = replacements[relPath];
// false is a valid value
if (redirect == null) {
redirect = replacements[relPath + ".js"];
if (redirect == null) {
redirect = replacements[relPath + ".json"];
}
}
// support exclude with "./someFile": false
if (redirect === false) {
return false;
}
if (redirect) {
return path.join(this._root, redirect);
}
return name;
}
read() {
if (this._content == null) {
this._content = JSON.parse(fs.readFileSync(this.path, "utf8"));
}
return this._content;
}
}
function getReplacements(pkg, mainFields) {
const replacements = mainFields
.map((name) => {
// If the field is a string, that doesn't mean we want to redirect the
// `main` file itself to anything else. See the spec.
if (!pkg[name] || typeof pkg[name] === "string") {
return null;
}
return pkg[name];
})
.filter(Boolean);
if (!replacements.length) {
return null;
}
return Object.assign({}, ...replacements.reverse());
}
module.exports = Package;