An empty statement is used to provide no statement, although the JavaScript syntax would expect one.
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Syntax
;
Description
The empty statement is a semicolon (;
) indicating that no statement will be executed, even if JavaScript syntax requires one.
The opposite behavior, where you want multiple statements, but JavaScript only allows a single one, is possible using a block statement, which combines several statements into a single one.
Examples
Empty loop body
The empty statement is sometimes used with loop statements. See the following example with an empty loop body:
let arr = [1, 2, 3]; // Assign all array values to 0 for (let i = 0; i < arr.length; arr[i++] = 0) /* empty statement */ ; console.log(arr); // [0, 0, 0]
Unintentional usage
It is a good idea to comment intentional use of the empty statement, as it is not really obvious to distinguish from a normal semicolon.
In the following example, the usage is probably not intentional:
if (condition); // Caution, this "if" does nothing! killTheUniverse() // So this always gets executed!!!
In the next example, an if...else
statement without curly braces ({}
) is used.
If three
is true
, nothing will happen, four
does not matter, and also the launchRocket()
function in the else
case will not be executed.
if (one) doOne(); else if (two) doTwo(); else if (three) ; // nothing here else if (four) doFour(); else launchRocket();
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'Empty statement' in that specification. |
Browser compatibility
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Empty statement (; ) | Chrome Full support 3 | Edge Full support 12 | Firefox Full support 1 | IE Full support 3 | Opera Full support 3 | Safari Full support 5 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 4.2 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
Legend
- Full support
- Full support