I was trying to below code in my Angular(v12.0.5) project and get this error.
var get_locale = moment.tz.zone('America/New_York').countries();
moment.locale(get_locale);
Error -

package.json -
"dependencies": {
"@angular/animations": "^12.0.5",
"@angular/cdk": "~12.2.13",
"@angular/common": "~12.0.3",
"@angular/compiler": "~12.0.3",
"@angular/core": "~12.0.3",
"@angular/forms": "~12.0.3",
"@angular/material": "~12.2.13",
"@angular/material-moment-adapter": "^13.2.2",
"@angular/platform-browser": "~12.0.3",
"@angular/platform-browser-dynamic": "~12.0.3",
"@angular/router": "~12.0.3",
"moment": "^2.29.1",
"rxjs": "~6.6.0",
"tslib": "^2.1.0",
"zone.js": "~0.11.4"
},
"devDependencies": {
"@angular-devkit/build-angular": "~12.0.3",
"@angular/cli": "~12.0.3",
"@angular/compiler-cli": "~12.0.3",
"@types/jasmine": "~3.6.0",
"@types/moment-timezone": "^0.5.30",
"@types/node": "^12.11.1",
"typescript": "~4.2.3"
}
Then I found the solution in moment doc -
const get_country = moment.tz.guess(true); // Asia/Calcutta
const get_locale = moment.locale(get_country); // en