I have an array of products like

```
[ 
{name:'Test1', id:1, prices: [ 20,25,30 ] },
{name:'Test2', id:2, prices: [ 21,26,31 ] },
...
]

```

each `product` has an array of `prices` depending of the product `sizes`.
I want to automatically create a new property in each object, which get the first price from corresponding array and writes in the `product` object

like

```
{name:'Test1', id:1, prices: [ 20,25,30 ], pr: 20 }

```