JSFiddle - React, Tailwind, and code Playground

HTML

<div ng-app="sample" ng-controller="TransformCtrl"></div>

JavaScript

angular.module('sample', [], function($httpProvider) {
    
    $httpProvider.defaults.transformRequest = function(data) {
        return btoa(JSON.stringify(data));
    };
    
    $httpProvider.defaults.transformResponse = function(data) {
        return JSON.parse(atob(data));
    };
    
}).controller('TransformCtrl', function($scope, $http){
    $http.post('url', {key:'value'});
});