Next JS advanced feature Content Security policy format - security

Question

I am adding security Policy headers to my application using Security headers advanced feature of next.js
Reference :https://nextjs.org/docs/advanced-features/security-headers
I am quiet clear of how to add the security policies to the next application except the Content Security policy,It does not show any format of the policy in the Documentation :
Taking help of next and developer.mozilla org I have some code in place,that I am attaching herewith. Can anybody help me with the correct format to define content-security policy in Next.JS
Code in Next.config.js
const cspPolicy = "default-src 'self';connect-src 'self','preview.contentful.com','*.flippenterprise.net', 'aq.flippenterprise.net','https://www.google-analytics.com','dpm.demdex.net','stats.g.doubleclick.net','lcljoefresh.sc.omtrdc.net','sfml.flippback.com','p.flipp.com','https://sentry.io/',";
const securityHeaders = [
{
key: 'Strict-Transport-Security',
value: 'max-age=63072000; includeSubDomains; preload'
},
{
key: 'X-Frame-Options',
value: 'SAMEORIGIN'
},
{
key: 'Content-Security-Policy',
value: cspPolicy
}
];
const headers = {
async headers() {
return [
{
// Apply these headers to all routes in your application.
source: '/(.*)',
headers: securityHeaders,
},
]
},
}
const nextConfig = {
env: {
search_key: process.env.search_key,
appDynamicsKey: process.env.appDynamicsKey,
ENVIRONMENT: process.env.ENVIRONMENT,
},
webpack5:false,
// https://nextjs.org/docs#customizing-webpack-config
webpack: (webpackConfig) => {
const { module = {} } = webpackConfig;
return {
...webpackConfig,
module: {
...module,
rules: [
...(module.rules || []),
{
test: /\.(txt|png|woff|woff2|eot|ttf|gif|jpg|ico|svg)$/,
use: {
loader: 'file-loader',
options: {
name: '[name]_[hash].[ext]',
publicPath: '/_next/static/files',
outputPath: 'static/files',
},
},
},
{
test: /\.spec.jsx$/,
loader: 'ignore-loader',
},
],
},
};
},
};
const sassOptions = {
sassLoaderOptions: {
outputStyle: 'compressed',
},
};
module.exports = withPlugins(
[[withSass, sassOptions], [withFonts], [withCSS], [withBundleAnalyzer]],
nextConfig,
headers,
);