An empty statement is used to provide no statement, although the JavaScript syntax would expect one.
An empty statement is used to provide no statement, although the JavaScript syntax would expect one.
;
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.
The empty statement is sometimes used with loop statements. See the following example with an empty loop body:
const 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]
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!!!
Specification |
---|
ECMAScript Language Specification # sec-empty-statement |
Desktop | Mobile | Server | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Opera | Safari | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | WebView Android | Deno | Node.js | ||
Empty |
3 | 12 | 1 | 3 | 5 | 18 | 4 | 10.1 | 4.2 | 1.0 | 4.4 | 1.0 | 0.10.0 |
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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/Empty