Literals - jsx/JSX GitHub Wiki

Literals of JSX is mostly the same to that of JavaScript.

Keywords

Keyword	Description
null [: type]	declares null, may have the type attributed
false	a boolean constant
true	a boolean constant

Contrary to JavaScript, there is no distinction between undefined and null.

Number Literal

Identical to JavaScript.

String Literal

Identical to JavaScript.

RegExp Literal

Identical to JavaScript.

Function Literal

// a function that takes no arguments, and returns void
function () : void {}

// a function that takes one argument (of number) and returns a number that in incremented by one
function (n : number) : number {
    return n + 1;
}

// the argument types and return types may be omitted (if it is deductable from the outer expression)
var sum = 0;
[ 1, 2, 3 ].forEach(function (e) {
    sum += e;
});
log sum; // 6

// short-handed
var sum = 0;
[ 1, 2, 3 ].forEach((e) -> { sum += e; });
log sum; // 6

// short-handed, single-statement function expression
var s = "a0b1c".replace(/[a-z]/g, (ch) -> ch.toUpperCase());
log s; // A0B1C

A statement starting with function is parsed as inner function declaration, as is by JavaScript. Surround function declaration with () if your intention is to create an anonymous function and call it immediately.

// inner function declaration (when used within a function declaration)
function innerFunc() : void {
    ...;
}

// create an anonymous function and execute immediately
(function () : void {
    ...;
})();

See also: Member Function in Class, Interface, and Mixin.