How to use the testcafe-hammerhead.processScript function in testcafe-hammerhead

export default function compileClientFunction (fnCode, dependencies, instantiationCallsiteName, compilationCallsiteName) {
    if (fnCode === ASYNC_TO_GENERATOR_OUTPUT_CODE)
        throw new ClientFunctionAPIError(compilationCallsiteName, instantiationCallsiteName, RUNTIME_ERRORS.regeneratorInClientFunctionCode);

    fnCode = makeFnCodeSuitableForParsing(fnCode);

    // NOTE: we need to recompile ES6 code for the browser if we are on newer versions of Node.
    fnCode = downgradeES(fnCode);
    fnCode = hammerhead.processScript(fnCode, false);

    // NOTE: check compiled code for regenerator injection: we have either generator
    // recompiled in Node.js 4+ for client or async function declared in function code.
    if (REGENERATOR_FOOTPRINTS_RE.test(fnCode))
        throw new ClientFunctionAPIError(compilationCallsiteName, instantiationCallsiteName, RUNTIME_ERRORS.regeneratorInClientFunctionCode);

    if (!TRAILING_SEMICOLON_RE.test(fnCode))
        fnCode += ';';

    const dependenciesDefinition = dependencies ? getDependenciesDefinition(dependencies) : '';

    return addBabelArtifactsPolyfills(fnCode, dependenciesDefinition);
}