JSFiddle - React, Tailwind, and code Playground

JavaScript

var object = '{\
        "apps": [\
            {\
                "applicationName": "myTestApp",\
                "keys": [\
                    {\
                        "key": "app-key",\
                        "value": "ZDM0"\
                    },\
                    {\
                        "key": "env-key",\
                        "value": "YTE1Mm"\
                    }\
                ]\
            },\
            {\
                "applicationName": "hello",\
                "keys": [\
                    {\
                        "key": "app-key",\
                        "value": "ZjIwZT"\
                    },\
                    {\
                        "key": "env-key",\
                        "value": "MDExMTc5N2"\
                    }\
                ]\
            }\
        ]\
    }';

var object = JSON.parse(object);
for(var i in object.apps){
    if("hello" == object.apps[i].applicationName)
        alert(i);
}