title: flatten nested object using lodash
body: <p>flatten, flattenDeep or flattenDepth of lodash only accept array. How to flatten nested object?</p>
  
  <pre><code>var data = {
    "dates": {
      "expiry_date": "30 sep 2018",
      "available": "30 sep 2017",
      "min_contract_period": [{
        "id": 1,
        "name": "1 month",
        "value": false
      }, {
        "id": 2,
        "name": "2 months",
        "value": true
      }, {
        "id": 3,
        "name": "3 months",
        "value": false
      }]
    },
    "price": {
      "curreny": "RM",
      "min": 1500,
      "max": 2000
    }
  }
  </code></pre>
  
  <p>I want nested property to be the first level, like expiry_date should be level 1, not within dates, and I think dates should be gone, it's not needed anymore. I can do it manually, use map() but I'm looking to use lodash to ease the task.</p>