## Explanation

From the jsLintErrors page about the warning [Function statements should not be placed in blocks][lint]:

> This error is raised to highlight **code that may not work as you expect it to**. In most environments Your code will run without error, but maybe not in the way you expect. In some environments it could cause a **fatal syntax error**.
>
> That's because `Function` declarations are *hoisted to the top of the scope* in which they appear.
>
>### Therefore, it is not possible to *conditionally* declare a function with a block statement. 

## Example

Let's explore issues raised by this problem with a simple example:



    if (true) {
        function example() {
            console.log('hello');
        }
    }

**The best case scenario** is that your code is confusing. In the above example, it looks like what you'd like to do is only declare access to the function *if* the condition is true.  However, when the function is hoisted to the top of the scope, it will actually be interpreted like this:



    function example() {
        console.log('hello');
    }
    if (true) {}

This is dangerous because it doesn't look like what you'd expect based on the original code.  The conditional block is actually empty (and unnecessary), and everybody has access to the function, regardless of whether the condition evaluates to true or false.

**The worst case scenario** is that the browser doesn't understand what to do with the nested function and throws a syntax error when trying to use it. This depends on the engine running JavaScript.  It seems like Firefox is one such engine. If you run the following code in Firefox, it will throw an error when executing the following code:





    if (true) {
        example();
        function example() {
            console.log('hello');
        }
    }



If you open up your console, you should see the following error:

![ReferenceError: example is not defined](http://i.imgur.com/mFyX0Zw.png)


## Solution

So how can you fix this?

### Use a function assignment instead of a function declaration

Here's a quick breakdown:


    
    // Declaration
    function declarationFunction() {}

    // Assignment
    var assignmentFunction = function() {}

**Function Assignments** are *not* hoisted to the top of the scope.  
**Function Declarations** are hoisted to the top of the scope.

So to conditionally set the example function, just assign it within the block like this:



    var example;
    if (true) {
        example = function() {
            console.log('hello');
        }
    }




[lint]: https://github.com/jamesallardice/jslint-error-explanations/blob/master/message-articles/function-in-block.md

I have the following code:
    
    if (typeof console === "object" && typeof console.error === "function") {
        function e(msg) {"use strict"; console.info(msg);}
    }

For which jsLint gives the following error:

> Function statements should not be placed in blocks. Use a function expression or move the statement to the top of the outer function.


Why is it giving this error and what does it mean?