/
nodeModulesPaths.ts
73 lines (64 loc) · 2.01 KB
/
nodeModulesPaths.ts
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/**
* Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* Adapted from: https://github.com/substack/node-resolve
*/
import * as path from 'path';
import type {Config} from '@jest/types';
import {sync as realpath} from 'realpath-native';
type NodeModulesPathsOptions = {
moduleDirectory?: Array<string>;
paths?: Array<Config.Path>;
};
export default function nodeModulesPaths(
basedir: Config.Path,
options: NodeModulesPathsOptions,
): Array<Config.Path> {
const modules =
options && options.moduleDirectory
? Array.from(options.moduleDirectory)
: ['node_modules'];
// ensure that `basedir` is an absolute path at this point,
// resolving against the process' current working directory
const basedirAbs = path.resolve(basedir);
let prefix = '/';
if (/^([A-Za-z]:)/.test(basedirAbs)) {
prefix = '';
} else if (/^\\\\/.test(basedirAbs)) {
prefix = '\\\\';
}
// The node resolution algorithm (as implemented by NodeJS and TypeScript)
// traverses parents of the physical path, not the symlinked path
let physicalBasedir;
try {
physicalBasedir = realpath(basedirAbs);
} catch (err) {
// realpath can throw, e.g. on mapped drives
physicalBasedir = basedirAbs;
}
const paths: Array<Config.Path> = [physicalBasedir];
let parsed = path.parse(physicalBasedir);
while (parsed.dir !== paths[paths.length - 1]) {
paths.push(parsed.dir);
parsed = path.parse(parsed.dir);
}
const dirs = paths
.reduce<Array<Config.Path>>(
(dirs, aPath) =>
dirs.concat(
modules.map(moduleDir =>
path.isAbsolute(moduleDir)
? aPath === basedirAbs
? moduleDir
: ''
: path.join(prefix, aPath, moduleDir),
),
),
[],
)
.filter(dir => dir !== '');
return options.paths ? dirs.concat(options.paths) : dirs;
}