Should not have unused variables JS-0128
Bug risk
Major
a year ago
—
2 years old
'chatLineParentSelector' is assigned a value but never used. Allowed unused vars must match /^_/u
12
13// 221211 트위치 프론트 업데이트로 선택자 변경
14// 221213 트위치 vod 재생 불가능하므로 실시간 채팅만 적용
15const chatLineParentSelector = `.chat-line__no-background`;16const chatTextSelector = `.text-fragment`;
17
18/**'streamers' is assigned a value but never used. Allowed unused vars must match /^_/u
24let iconRenderOptions = {};
25let streamerIcons = [];
26let streamerIconStats = {};
27let streamers = [];28
29const preRenderedIcons = {
30 image: {},'streamerIconStats' is assigned a value but never used. Allowed unused vars must match /^_/u
23let iconStats = {};
24let iconRenderOptions = {};
25let streamerIcons = [];
26let streamerIconStats = {};27let streamers = [];
28
29const preRenderedIcons = {'streamerIcons' is assigned a value but never used. Allowed unused vars must match /^_/u
22let iconMetadata = {};
23let iconStats = {};
24let iconRenderOptions = {};
25let streamerIcons = [];26let streamerIconStats = {};
27let streamers = [];
28'iconRenderOptions' is assigned a value but never used. Allowed unused vars must match /^_/u
21let browserSyncData = {};
22let iconMetadata = {};
23let iconStats = {};
24let iconRenderOptions = {};25let streamerIcons = [];
26let streamerIconStats = {};
27let streamers = [];
Description
Found variables that are declared but not used anywhere.
NOTE: In browser applications, DeepSource recommends the use of ESModules over regular
text/javascriptscripts. Currently, we don't support variables that are not explicitly exported, and are injected into other scripts by being included in an HTML file
Unused variables are most often the result of incomplete refactoring. They can lead to confusing code and minor performance hitches.
NOTE: If you have intentionally left a variable unused, we suggest you to prefix the variable name with a _ to prevent them from being flagged by DeepSource.
Bad Practice
// Write-only variables are not considered as used.
let y = 10;
y = 5;
// A variable that modifies only itself isn't considered used.
let z = 0;
z = z + 1;
// Unused argument
(function(x) {
return 5;
})();
// Unused recursive functions also raise this issue.
function fact(n) {
if (n < 2) return 1;
return n * fact(n - 1);
}
// When a function definition destructures an array,
// unused entries from the array also cause warnings.
function getY([x, y]) {
return y;
}
Recommended
let x = 10;
alert(x);
((arg1) => {
return arg1;
})();
let myFunc;
myFunc = (n) => {
// this is legal
if (n < 0) myFunc();
};
// this is also considered legal
console.log(declaredLater);
var declaredLater;
// Only the second argument from the descructured array is used.
function getY([, y]) {
return y;
}