What am I doing wrong here?

```
for (var yearx = 0; yearx < (2018 - 2011); yearx++){
    json.course[i].year[yearx] = {'value':eval(2011 + yearx),'term':[{'value':e}]};
//add terms`

```

…causes:

> 
> Typescript Error
> 
> 
> Argument of type 'number' is not assignable to parameter of type
>  'string'
> 
> 
>