Proper way to re-initialize the data in VueJs 2.0

Question

I was going through this answer on SO : Is there a proper way of resetting a component's initial data in vuejs?

However, the current method is not allowed now and VueJS prohibits changing the $data var.

As you can see here in this https://github.com/vuejs/vue/issues/2873 ( $data is not allowed to be modified. )

So if I try the above method, I am getting a VueJS warning:

[Vue warn]: Avoid replacing instance root $data. Use nested data properties instead.

Here is my JS code,

function initialState () {
        return {
            h2: 0,
            ch4: 0,
            c2h6: 0,
            c2h4: 0,
            c2h2: 0,
            c3h8: 0,
            c3h6: 0,
            co: 0,
            co2: 0,
            o2: 0,
            n2: 0,
            selected: ''
        }
    }
    export default {
        name: 'something',
        data () {
            return initialState() // This is working fine 
        },
        computed: {
            tdcg: function () {
                // some logic here...
            }
        },
        methods: {
            resetFields: function () {
                this.$data = initialState() // --> This is what I want to achieve!
            }
        }
    }

So what is the correct and the easiest way of re initialising my data?

Answer 1

You can use Object.assign to iterate through all properties and assign them:

export default {
    data () {
        return {
            h2: 0,
            // other attributes...
        };
    },
    methods: {
        resetFields () {
            Object.assign(this.$data, this.$options.data.call(this));
        }
    }
}

Here's a demo fiddle: https://jsfiddle.net/797yyvtz/

---

Note: I'm using this.$options.data to call the original data method again to get a fresh copy of the data. No need for a separate initialState function. The data method is the initial state function.