function _getRushVersion()

in common/scripts/install-run-rush.js [127:147]

• 19 lines of code
• 3 McCabe index (conditional complexity)

function _getRushVersion(logger) {
    const rushPreviewVersion = process.env[RUSH_PREVIEW_VERSION];
    if (rushPreviewVersion !== undefined) {
        logger.info(`Using Rush version from environment variable ${RUSH_PREVIEW_VERSION}=${rushPreviewVersion}`);
        return rushPreviewVersion;
    }
    const rushJsonFolder = findRushJsonFolder();
    const rushJsonPath = path__WEBPACK_IMPORTED_MODULE_0__.join(rushJsonFolder, RUSH_JSON_FILENAME);
    try {
        const rushJsonContents = fs__WEBPACK_IMPORTED_MODULE_1__.readFileSync(rushJsonPath, 'utf-8');
        // Use a regular expression to parse out the rushVersion value because rush.json supports comments,
        // but JSON.parse does not and we don't want to pull in more dependencies than we need to in this script.
        const rushJsonMatches = rushJsonContents.match(/\"rushVersion\"\s*\:\s*\"([0-9a-zA-Z.+\-]+)\"/);
        return rushJsonMatches[1];
    }
    catch (e) {
        throw new Error(`Unable to determine the required version of Rush from ${RUSH_JSON_FILENAME} (${rushJsonFolder}). ` +
            `The 'rushVersion' field is either not assigned in ${RUSH_JSON_FILENAME} or was specified ` +
            'using an unexpected syntax.');
    }
}