Write a function that simply repeats the string a given number of times:

repeatString('hey', 3) // returns 'heyheyhey'

This function will take two arguments, string and num. If num is a negative number, return the string 'ERROR' instead.

Use loops to implement repeatString rather than using the builtin String.prototype.repeat which has the same behaviour.

Note: The exercises after this one will not have arguments provided as this one does - you will need to provide them yourself from now on. So read each exercise's README carefully to see what kinds of arguments will be expected.

• What inputs does the function need to achieve its goal?

• How can you iteratively build up the final string, using one of the inputs to control the repetition?