Return statement

Overview

return statement is used for returning back from a function.

function func() {
    return 10;
}

Expession

return statement can have any expression and returning the evaluated value to caller function. If there is no expression, null will be returned Implicitly.

function func1() {
    return 10 + funcX();    // if funcX() returns 5, then func1() returns 15.
}
function func2() {
    return;                 // same as `return null`.
}

if-modifier

return statement can have if-modifier. See the example below.

return 10 if (a < 10);  // return 10 if `a` is less than 10.
return if (b < 10);     // return null if `b` is less than 10.

Examples

Example 1. Normal case

Code

function func() {
    return 10;
}
System.println(func());

Result

10

Example 2. Without expression

Code

function func() {
    return;
}
System.println(func().isUndefined ? "null" : "defined");

Result

null

Example 3. if-modifier (1)

Code

function func(a) {
    return if (a < 10);
    return a * 20;
}
System.println((a = func( 8)).isUndefined ? "null" : a);
System.println((a = func( 9)).isUndefined ? "null" : a);
System.println((a = func(10)).isUndefined ? "null" : a);

Result

null
null
200

Example 4. if-modifier (2)

Code

function func(a) {
    return a * 20 if (a < 10);
    return;
}
System.println((a = func( 8)).isUndefined ? "null" : a);
System.println((a = func( 9)).isUndefined ? "null" : a);
System.println((a = func(10)).isUndefined ? "null" : a);

Result

160
180
null