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JavaScript JavaScript Functions Arrow Functions Function Challenge Solution

Posted by pacificbee
pacificbee
2,205 Points

If statement syntax inside arrow functions

When trying to find the solution on my own, I used the code below based on what's been taught in previous lessons but I get a console error that says "Uncaught SyntaxError: Unexpected end of input." in regards to the last line.

If I follow the solution and remove "else {" it suddenly works. Why is that? I thought those were needed for an if statement to work. 

const randomNumber = (lower, upper) => {
  if ( isNaN(lower) || isNaN(upper)) { 
   console.log( `Please enter a number. You input a string.` ); 

} else { 
   return Math.floor(Math.random() * (upper - lower + 1)) + lower;
};

// Call the function and pass it different values.

  console.log( randomNumber( 5, 10) );

1 Answer

Steven Parker
Steven Parker
231,275 Points
Steven Parker
Steven Parker
231,275 Points

The video solution uses a "throw" when an error is made instead of "console.log". The "throw" causes the function to end so no "else" is needed.

You need the "else" here because the function keeps running after logging.

pacificbee
pacificbee
2,205 Points

I should've added this when I first posted my Q but that code is returning an error for the last line. The error is "Uncaught SyntaxError: Unexpected end of input."

Do you know why that is? I thought if statements needed "else {" in order to work.

Steven Parker
Steven Parker
231,275 Points
Steven Parker
Steven Parker
231,275 Points 
    return Math.floor(Math.random() * (upper - lower + 1)) + lower;
  }  // <-- this brace to close the "else" was missing
};    // <-- this brace ends the function

And an "else" is entirely optional for the syntax (though sometimes it may be needed for the program logic to work).