Declaring array in react typescript tsx file gives "error TS1109: Expression expected"

Question

When I try to declare an array within a React (but using typescript) tsx file I get the error message:

"error TS1109: Expression expected"

  public render() {
    return (
      <div>
        {  var nums:number[] = [1,2,3,3]  }  // ERROR HERE
      </div>
    )
  }

Answer 1

Your code var nums:number[] = [1,2,3,3] is not an expression. It's a statement.

An expression would be [1,2,3,3].

Easy way to think about it

Anything that can be assigned to a variable is an expression. You wouldn't do:

const foo = var nums:number[] = [1,2,3,3]; // ERROR `var nums:number[] = [1,2,3,3]` is not an expression

Solution to declaring

Do it out of JSX e.g.

public render() {
    var nums:number[] = [1,2,3,3]
    return (
      <div>
        {  nums[0]  }
      </div>
    )
  }