Why won't passing `''.trim()` straight to `[].map()`'s callback work?

Question

I have an array of strings. I want to trim each string in the array.

I thought using [].map() with \'\'.trim() would work...

[\' a\', \' b   \', \'c         


        

Answer 1

trim is on the String prototype, meaning that it expects the this context to be that of a string where as the map method on Array provides the current array item as the first argument and the this context being the global object.