in add-cors-header/index.js [1:13]
function handler(event) {
var request = event.request;
var response = event.response;
// If Access-Control-Allow-Origin CORS header is missing, add it.
// Since JavaScript doesn't allow for hyphens in variable names, we use the dict["key"] notation.
if (!response.headers['access-control-allow-origin'] && request.headers['origin']) {
response.headers['access-control-allow-origin'] = {value: request.headers['origin'].value};
console.log("Access-Control-Allow-Origin was missing, adding it now.");
}
return response;
}