remove ifs around function expressions

[pgarciacamou]

Function expressions are hoisted outside of block scopes, in other words, JavaScript will define the functions anyway. Thus, the HAS_UINT8ARRAY and HAS_BUFFERS if statements surrounding the functions do not play any role in this library.

JavaScript bundlers, such as Webpack, are assuming you are trying to declare the function inside the if's block scope only to be used inside the if statement. Like so:

if (HAS_BUFFERS) {
    var _bufferCharCodeAt = function (buf, offset) {
        return buf.readUInt8(offset);
    }
	// ...
}

// later in the code, webpack assumes "bufferCharCodeAt" is global:
something = bufferCharCodeAt; // note that there is no underscore.

This causes the library to error out with "bufferCharCodeAt is not defined" error. Which can be quickly mitigated by understanding scope in JavaScript and removing the unnecessary if statements from function expression declarations.