In the world of JavaScript (ECMAScript 5), functions are highly esteemed (referred to as "first-class functions").
This unique characteristic allows us to treat functions as expressions, which means they can produce values and even include other expressions within them. For example:
var exp0 = (exp1) + exp2 - exp3.function();In the snippet above, there exist a total of 8 expressions that we can identify: exp0, exp1, (exp1), exp2, (exp1) + exp2, exp3, exp3.function(), and (exp1) + exp2 - exp3.function().
This leads us to the realization that functions' versatility as expressions enables correct syntax in the following scenarios:
A perfect illustration would be:
var my_function_0 = function a() {}Also valid:
var my_function_1 = function(){}` reflects the concept of an anonymous function expression.
Both of these examples serve as testaments to the fact that both named and anonymous function expressions hold inherent value as programming components.
Now, let's delve into the code snippet below for further exploration:
function requiredIdentifier() {}
Contrary to named or anonymous function expressions, this piece of code does not fall under either category; instead, it represents what is known as a function declaration.
This prompts the essential question at hand:
Can a declared function have a tangible value associated with it?
To put it another way: Does a declared function qualify as an expression, despite not falling into the named or anonymous function expression classification?