Duplicate conditions in
if-else-if chains JS-0034
Bug risk
5 months ago
—
5 months old
This branch can never execute. Its condition is a duplicate or covered by previous conditions in the if-else-if chain.
46 $('.adjhide').hide();
47 $('.inrec-area').slideDown();
48 }
49 else if(selectedAdj == 'accu'){ 50 $('.adjhide').hide();
51 $('.accu-area').slideDown();
52 }
Description
When an if-else-if chain has identical conditions, a duplicate will evaluate the same true or false value as the identical expression earlier in the chain, meaning that its branch can never execute.
The issue can be autofixed by DeepSource by removing the duplicate if statement and its code block.
This issue can be autofixed.
The fixer will remove the duplicate if statement and its code block, for example, given the code sample having a duplicate if condition:
if (a) {
func()
} else if (b) {
handler()
} else if (b) {
change()
}
The fixer will remove the later if condition i.e, the one else if (b) and its body, so the output will be
if (a) {
func()
} else if (b) {
handler()
}
Bad Practice
if (isSomething(x)) {
func();
} else if (isSomething(x)) {
handler();
}
if (a) {
func();
} else if (b) {
handler();
} else if (c && d) {
change();
} else if (c && d) {
toggle();
} else {
cb();
}
if (n === 1) {
func();
} else if (n === 2) {
handler();
} else if (n === 3) {
change();
} else if (n === 2) {
toggle();
} else if (n === 5) {
cb();
}
Recommended
if (isSomething(x)) {
func();
} else if (isSomethingElse(x)) {
handler();
}
if (a) {
func();
} else if (b) {
handler();
} else if (c && d) {
change();
} else if (c && e) {
toggle();
} else {
cb();
}
if (n === 1) {
func();
} else if (n === 2) {
handler();
} else if (n === 3) {
change();
} else if (n === 4) {
toggle();
} else if (n === 5) {
cb();
}