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JavaScript React Router 4 Basics Going Further with Routing Navigating Routes Programmatically

Posted by Mark Moulton
Mark Moulton
4,876 Points

Can't declare function in react component

I get an error saying unrecognized token on the var keyword. Does anybody know why?

1 Answer

Chris Martinez
Chris Martinez
11,715 Points
Chris Martinez
Chris Martinez
11,715 Points

Without code, I can't say for certain if this is the answer, but from from previous experience, my guess is that you are trying to assign a variable in the context of declaring a class-based component. Ex:

class Home extends Component {
  someAction = (e) =>{
 }
  someProp: 'peanuts';
 anotherProp: 'cola';

}

anything you write between the first and last curly brackets you are in actuality writing in ES6 style object notation, so someProp and someAction are actually a property and a method, respectively, and we never use the "var/let/const" keywords in this name space, since everything is written directly to the object.

In the case of this of the Featured component, we are writing a Functional Component

const Featured = ({match}) => {
  var name = match.params.name;
  var topic = match.params.topic;
 var someFunc = ()=>{
......
}

}

This is really like any other normal function in JS, and anything in between is actually a block level variable. You're not writing to a "Featured" Object, you're creating a block scope.

Hope this helps!