exports.js

//we will use this again
function foo(){
    function bar(){
    } 
    return bar;
}

//export by itself

//with a declaration
export function foo(){
    function bar(){
    } 
    return bar;
}
//exports that function as foo

//in es6 we get more types of declarations so
export class Foo{

}
// exports Foo as Foo

//but you can't export that variable
export foo;
// error

//and it's not an expression so you can't do this
//even if what returned was legal (which it isn't)
export foo();
// error

//export a variable declaration (VariableStatement)
export let bar = foo();
// exports bar as bar

//normal rules for right hand side
export let a = [thing1, thing2];
//exports array as a

//chained variable expressions work too
export var a = 1, b = 2;
//exports a as 1 and b as 2

//you're still declaring the variables so you can't
//use a name that is already there
var a = 1;
export var a = 2;
//error


// export defaults
// must be a AssignmentExpression
// aka anything on the right hand side of a var a = b;

export default foo;
//foo is exported as default

export default foo();
//bar is exported as defult

export default function (){}
//function exported as default

export default let a = [thing1, thing2];
//error

export default [thing1, thing2];
//export list as default

//export expressions

//export a current variable
export { foo }
// export foo as foo

//export a current variable with a different name
export { foo as bar }
// export foo as bar

//but it can't be an expression, just a name (IdentifierReference or IdentifierName)
export { function(){} as bar }
//error

export foo;
// syntax error:  you want export { foo };

export foo();
// syntax error

export default let a = [thing1, thing2];
// syntax error

thanks I updated it