var cacheNpmPackage = function()

in gulpfile.js [910:992]

• 74 lines of code
• 9 McCabe index (conditional complexity)

var cacheNpmPackage = function (name, version) {
    // Validate the parameters.
    if (!name) {
        throw new Error('Parameter "name" cannot be null or empty.');
    }

    if (!version) {
        throw new Error('Parameter "version" cannot be null or empty.');
    }

    // Short-circuit if already downloaded.
    gutil.log('Downloading npm package ' + name + '@' + version);
    var targetPath = path.join(_tempPath, 'npm', name, version);
    if (shell.test('-d', targetPath)) {
        console.log('Package already cached. Skipping.');
        return;
    }

    // Delete any previous partial attempt.
    var partialPath = path.join(_tempPath, 'partial', 'npm', name, version);
    if (shell.test('-d', partialPath)) {
        shell.rm('-rf', partialPath);
    }

    // Write a temporary package.json file to npm install warnings.
    //
    // Note, write the file higher up in the directory hierarchy so it is not included
    // when the partial directory is moved into the target location
    shell.mkdir('-p', partialPath);
    var pkg = {
        "name": "temp",
        "version": "1.0.0",
        "description": "temp to avoid warnings",
        "main": "index.js",
        "dependencies": {},
        "devDependencies": {},
        "repository": "http://norepo/but/nowarning",
        "scripts": {
            "test": "echo \"Error: no test specified\" && exit 1"
        },
        "author": "",
        "license": "MIT"
    };
    fs.writeFileSync(
        path.join(_tempPath, 'partial', 'npm', 'package.json'),
        JSON.stringify(pkg, null, 2));

    // Validate npm is in the PATH.
    var npmPath = shell.which('npm');
    if (!npmPath) {
        throw new Error('npm not found.  ensure npm 3 or greater is installed');
    }

    // Validate the version of npm.
    var versionOutput = cp.execSync('"' + npmPath + '" --version');
    var npmVersion = versionOutput.toString().replace(/[\n\r]+/g, '')
    console.log('npm version: "' + npmVersion + '"');
    if (semver.lt(npmVersion, NPM_MIN_VER)) {
        throw new Error('npm version must be at least ' + NPM_MIN_VER + '. Found ' + npmVersion);
    }

    // Make a node_modules directory. Otherwise the modules will be installed in a node_modules
    // directory further up the directory hierarchy.
    shell.mkdir('-p', path.join(partialPath, 'node_modules'));

    // Run npm install.
    shell.pushd(partialPath);
    try {
        var cmdline = '"' + npmPath + '" install ' + name + '@' + version;
        var result = cp.execSync(cmdline);
        gutil.log(result.toString());
        if (result.status > 0) {
            throw new Error('npm failed with exit code ' + result.status);
        }
    }
    finally {
        shell.popd();
    }

    // Move the intermediate directory to the target location.
    shell.mkdir('-p', path.dirname(targetPath));
    shell.mv(partialPath, targetPath);
}