Found unused expressions JS-0093
Bug risk
Minor
a year ago
—
a year old
Found unused expression
465 else if(document.querySelector(hiddenChatSelector) !== null)
466 {
467 logger.info(`Chat area is hidden!`);
468 chatAreaObserver && chatAreaObserver.disconnect();469 isChatHidden = true;
470 }
471}Found unused expression
458 {
459 logger.info(`Chat area is recovered!`);
460 if(runner) runner.stop = true;
461 streamChatObserver && streamChatObserver.disconnect();462 runner = new Runner(false, 1);
463 isChatHidden = false;
464 }Found unused expression
424 /**
425 * 이 부분은 특수 키가 아닐 때만 실행됨 => 변수 초기화
426 */
427 iconSelectorList.children[iconSelectorCursor] && iconSelectorList.children[iconSelectorCursor].classList.remove("selected");428 iconSelectorCursor = -1;
429}
430Found unused expression
347 if(iconSelectorList.children[iconSelectorCursor])
348 {
349 iconSelectorList.children[iconSelectorCursor].classList.remove("selected");
350 iconSelectorList.children[iconSelectorCursor]._tippy && iconSelectorList.children[iconSelectorCursor]._tippy.destroy();351 }
352 iconSelectorCursor = (iconSelectorCursor <= 0) ? iconSelectorList.children.length - 1 : iconSelectorCursor - 1;
353 iconSelectorCursorArrowCount = Math.max(iconSelectorCursorArrowCount-1, -text.length);Found unused expression
319 if(iconSelectorList.children[iconSelectorCursor])
320 {
321 iconSelectorList.children[iconSelectorCursor].classList.remove("selected");
322 iconSelectorList.children[iconSelectorCursor]._tippy && iconSelectorList.children[iconSelectorCursor]._tippy.destroy();323 }
324 iconSelectorCursor = (iconSelectorList.children.length === iconSelectorCursor + 1)
325 ? 0
Description
An unused expression that does not affect the state of the program indicates a logic error.
For example, if a programmer wants to increment the value of a variable a by one, and intends to do so through this code:
let a = 0
a = a + 1
console.log(a) // output 1
But because of a typo, writes the following:
let a = 0
a + 1
console.log(a)
Here, the expression a + 1 does nothing meaningful in the program's runtime.
The expression is thus considered "unused" and should be removed.
Bad Practice
0
if(0) 0
{0}
f(0), {}
a, b()
c = a, b;
a() && function namedFunctionInExpressionContext () {f();}
(function anIncompleteIIFE () {});
injectGlobal`body{ color: red; }`
Recommended
{} // In this context, this is a block statement, not an object literal
{myLabel: someVar} // In this context, this is a block statement with a label and expression, not an object literal
function namedFunctionDeclaration () {}
(function aGenuineIIFE () {}());
f()
a = 0
new C
delete a.b
void a