JSFiddle - React, Tailwind, and code Playground

HTML

<div ng-app="app">
  <div ng-controller="GeojsonController">
    <textarea ng-model="geojson" ng-change="update()"></textarea>
    <p>Geojson is: {{geo | json}} </p>
  </div>
</div>

JavaScript

angular.module('app', [])
  .controller('GeojsonController', ['$scope', function($scope) {
    $scope.geo = {
      "type": "FeatureCollection"
    };
    $scope.geojson = angular.toJson($scope.geo);
    
    $scope.update = function() {
    	$scope.geo = angular.fromJson($scope.geojson);
    }
  }]);