iterate over jsonarray firebase cloud functions

I am trying to to parse json data from request body. The body I get in request is like :

{ members: '[{"ContactName":"abc","ContactNumber":"+92------","Turn":"28/04/2017","mData":0}]',
  cid: '-Kl8Yhi-3qCQ4E-iDFj6',
  committeedetails: '{"admin":"+923064664223","description":"xyz\\nMembers 1\\nPKR 10"}' }

and I get members from it as:

var body = req.body;
var members = body.members;

and console log for members is:

[{"ContactName":"abc","ContactNumber":"+92--------","Turn":"28/04/2017","mData":0}]

I want to iterate over this I have tried:

members.forEach(function(obj) { console.log("members",obj.id); });

Now issue is that I cant iterate over this json array. It throughs typo error :

TypeError: members.forEach is not a function
    at exports.shareTurnWithMembers.functions.https.onRequest (/user_code/index.js:110:13)
    at cloudFunction (/user_code/node_modules/firebase-functions/lib/providers/https.js:26:47)
    at /var/tmp/worker/worker.js:638:7
    at /var/tmp/worker/worker.js:622:9
    at _combinedTickCallback (internal/process/next_tick.js:67:7)
    at process._tickDomainCallback (internal/process/next_tick.js:122:9)

from some other questions I have also tried:

for(var i= 0; i<members.length; i++){
        var obj = members[i];
        console.log("members"+i, obj);
    }

and :

for (var key in members){
            console.log("members",key);
        }

these always through members length about 100. and log each character in the array.

Can anybody here correct me to iterate over json array containing json objects?

via Saira Nawaz