命名导出函数声明后是否需要分号？

Question

First, this is NOT a question about ASI. I'm not asking whether or not automatic semicolon insertion applies here (well, I kind of am, but that opening statement is an attempt at avoiding arguments between whether I should or shouldn't use a semicolon because asi will take care of it for me...)

I know not to put a semicolon after a function declaration...

function foo() { 
  // do stuff
} // no semicolon

But do I need a semicolon after export ing a function declaration?

export function foo() {
  // do stuff
} // semicolon or not to semicolon?

In either case, I would also love to know why.

Answer 1

No, you do not need a semi-colon, though adding one will do no harm.

If we look at the ES6 spec , you will see that this signature is considered a declaration and, like normal function declarations, does not need a semicolon after it:

export Declaration

The statements that need to be followed by a semi-colon (whether explicit or implicit) are noted as such in that document. For example:

export * FromClause ;

There the ; is mandatory. In the declaration, it is not. Of course, inserting the semicolon will not do any harm; the JS interpreter will treat it as an empty statement.

Answer 2

No, you don't need a semicolon here. See this example from MDN :

 export default function() {} // or 'export default class {}' // there is no semi-colon here 

See also the ECMAScript specification :

Syntax

 ExportDeclaration : export * FromClause ; export ExportClause[~Local] FromClause ; export ExportClause[+Local] ; export VariableStatement[~Yield, ~Await] export Declaration[~Yield, ~Await] export defaultHoistableDeclaration[~Yield, ~Await, +Default] export defaultClassDeclaration[~Yield, ~Await, +Default] export default[lookahead ∉ { function, async [no LineTerminator here] function, class }]AssignmentExpression[+In, ~Yield, ~Await] ; 

As you see, there's no semicolon after Declaration .