Should not have unused variables JS-0128
Bug risk
6 months ago
—
7 months old
'getCookies' is defined but never used. Allowed unused vars must match /^_/u
1import { setCookie, getCookie, getCookies } from 'cookies-next'; 2import jwt from "jsonwebtoken";
3import { Redis } from "@upstash/redis";
4import nodemailer from "nodemailer";'Footer' is defined but never used. Allowed unused vars must match /^_/u
1import Head from 'next/head';
2import { useRouter } from 'next/router'
3import NavBar from "../../../components/nav.js";
4import Footer from "../../../components/footer.js"; 5import { darkMode } from "../../../globalStates/theme.js";
6import useSWR from 'swr';
7'NavBar' is defined but never used. Allowed unused vars must match /^_/u
1import Head from 'next/head';
2import { useRouter } from 'next/router'
3import NavBar from "../../../components/nav.js"; 4import Footer from "../../../components/footer.js";
5import { darkMode } from "../../../globalStates/theme.js";
6import useSWR from 'swr';'Head' is defined but never used. Allowed unused vars must match /^_/u
1import Head from 'next/head'; 2import { useRouter } from 'next/router'
3import NavBar from "../../../components/nav.js";
4import Footer from "../../../components/footer.js";'capitalizeFirstLetter' is defined but never used. Allowed unused vars must match /^_/u
7
8const fetcher = (...args) => fetch(...args).then(res => res.json());
9
10function capitalizeFirstLetter(string) {11 return string.charAt(0).toUpperCase() + string.slice(1);
12}
13
Description
Found variables that are declared but not used anywhere.
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.
var y = 10;
y = 5;
// A variable that modifies only itself isn't considered used.
var 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
var 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;
}