const output = void 1;console.log(output);// Expected output: undefinedvoid console.log("expression evaluated");// Expected output: "expression evaluated"void (function iife() {  console.log("iife is executed");})();// Expected output: "iife is executed"void function test() {  console.log("test function executed");};try {  test();} catch (e) {  console.log("test function is not defined");  // Expected output: "test function is not defined"}

void expression;

void 2 == "2"; // undefined == '2', falsevoid (2 == "2"); // void true, undefined

void (function iife() {  var bar = function () {};  var baz = function () {};  var foo = function () {    bar();    baz();  };  var biz = function () {};  foo();  biz();})();

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참고:#"새지_않는_화살표_함수" >

새지 않는 화살표 함수

Arrow functions introduce a short-hand braceless syntax that returns an expression. This can cause unintended side effects by returning the result of a function call that previously returned nothing. To be safe, when the return value of a function is not intended to be used, it can be passed to the void operator to ensure that (for example) changing APIs do not cause arrow functions' behaviors to change.

button.onclick = () => void doSomething();

This ensures the return value ofdoSomething changing fromundefined totrue will not change the behavior of this code.

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