JSFiddle - React, Tailwind, and code Playground

JavaScript

var jsonObject = {
    "sync_contact_list": [
        {
            "name": "c",
            "number": "789",
            "email": ""
        },
        {
            "name": "b",
            "number": "123",
            "email": "a@a.com"
        },
        {
            "name": "a",
            "number": "416",
            "email": ""
        }
    ]
};

// show result
var output = '';

for (var i=0; i<jsonObject['sync_contact_list'].length; i++){
    var bit = jsonObject['sync_contact_list'][i];
    output += '[name: "' + bit['name'] +
        '", number: "' + bit['number'] +
        '", email: "' + bit['email'] +
        ']\n';
};
alert(output);