react-native/local-cli/util/findSymlinkedModules.js

111 lines
3.4 KiB
JavaScript

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* @format
* @flow
*/
const path = require('path');
const fs = require('fs');
/**
* Find symlinked modules inside "node_modules."
*
* Naively, we could just perform a depth-first search of all folders in
* node_modules, recursing when we find a symlink.
*
* We can be smarter than this due to our knowledge of how npm/Yarn lays out
* "node_modules" / how tools that build on top of npm/Yarn (such as Lerna)
* install dependencies.
*
* Starting from a given root node_modules folder, this algorithm will look at
* both the top level descendants of the node_modules folder or second level
* descendants of folders that start with "@" (which indicates a scoped
* package). If any of those folders is a symlink, it will recurse into the
* link, and perform the same search in the linked folder.
*
* The end result should be a list of all resolved module symlinks for a given
* root.
*/
module.exports = function findSymlinkedModules(
projectRoot: string,
ignoredRoots?: Array<string> = [],
) {
const timeStart = Date.now();
const nodeModuleRoot = path.join(projectRoot, 'node_modules');
const resolvedSymlinks = findModuleSymlinks(nodeModuleRoot, [
...ignoredRoots,
projectRoot,
]);
const timeEnd = Date.now();
console.log(
`Scanning folders for symlinks in ${nodeModuleRoot} (${timeEnd -
timeStart}ms)`,
);
return resolvedSymlinks;
};
function findModuleSymlinks(
modulesPath: string,
ignoredPaths: Array<string> = [],
): Array<string> {
if (!fs.existsSync(modulesPath)) {
return [];
}
// Find module symlinks
const moduleFolders = fs.readdirSync(modulesPath);
const symlinks = moduleFolders.reduce((links, folderName) => {
const folderPath = path.join(modulesPath, folderName);
const maybeSymlinkPaths = [];
if (folderName.startsWith('@')) {
const scopedModuleFolders = fs.readdirSync(folderPath);
maybeSymlinkPaths.push(
...scopedModuleFolders.map(name => path.join(folderPath, name)),
);
} else {
maybeSymlinkPaths.push(folderPath);
}
return links.concat(resolveSymlinkPaths(maybeSymlinkPaths, ignoredPaths));
}, []);
// For any symlinks found, look in _that_ modules node_modules directory
// and find any symlinked modules
const nestedSymlinks = symlinks.reduce(
(links, symlinkPath) =>
links.concat(
// We ignore any found symlinks or anything from the ignored list,
// to prevent infinite recursion
findModuleSymlinks(path.join(symlinkPath, 'node_modules'), [
...ignoredPaths,
...symlinks,
]),
),
[],
);
return [...new Set([...symlinks, ...nestedSymlinks])];
}
function resolveSymlinkPaths(maybeSymlinkPaths, ignoredPaths) {
return maybeSymlinkPaths.reduce((links, maybeSymlinkPath) => {
if (fs.lstatSync(maybeSymlinkPath).isSymbolicLink()) {
const resolved = path.resolve(
path.dirname(maybeSymlinkPath),
fs.readlinkSync(maybeSymlinkPath),
);
if (ignoredPaths.indexOf(resolved) === -1 && fs.existsSync(resolved)) {
links.push(resolved);
}
}
return links;
}, []);
}