ReactJS can't access “this” methods

Question

I am trying to pass a method to a child component to handle onclick events. I saw a lot of examples online, but I can\'t get it working. When I am inside the render function

Answer 1

this is undefined because the map callback does not know what it is. The simplest way to solve this is to pass a second argument, and it will use that as this in the callback:

var thumbsNodes = this.state.data.map(function(thumb) {
  console.log(this.handleClick)
  return 
}, this)

More: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map