old URL : https://happy.info/oldURL
new URL : https//happy.info/newURL
edit firebase.json
{ "hosting": { "public": "public", "ignore": [ "firebase.json", "**/.*", "**/node_modules/**" ], "cleanUrls": true, "redirects": [{ "source": “/oldURL”, "destination": "https://happy.info/newURL”, "type": 301 } ] } }
redirectsのsourceに、“/oldURL”
destinationに"https://happy.info/newURL”、typeに301と記載してfirebaseをデプロイすればOK