noRedeclare (since v12.0.0)
This rule is recommended by Rome.
Disallow variable, function, class, and type redeclarations in the same scope.
Source: https://typescript-eslint.io/rules/no-redeclare
Examples
Invalid
var a = 3;
var a = 10;suspicious/noRedeclare.js:2:5 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
✖ Shouldn't redeclare 'a'. Consider to delete it or rename it.
1 │ var a = 3;
> 2 │ var a = 10;
│ ^
3 │
ℹ 'a' is defined here:
> 1 │ var a = 3;
│ ^
2 │ var a = 10;
3 │
let a = 3;
let a = 10;suspicious/noRedeclare.js:2:5 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
✖ Shouldn't redeclare 'a'. Consider to delete it or rename it.
1 │ let a = 3;
> 2 │ let a = 10;
│ ^
3 │
ℹ 'a' is defined here:
> 1 │ let a = 3;
│ ^
2 │ let a = 10;
3 │
function f() {}
function f() {}suspicious/noRedeclare.js:2:10 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
✖ Shouldn't redeclare 'f'. Consider to delete it or rename it.
1 │ function f() {}
> 2 │ function f() {}
│ ^
3 │
ℹ 'f' is defined here:
> 1 │ function f() {}
│ ^
2 │ function f() {}
3 │
class C {
static {
var c = 3;
var c = 10;
}
}suspicious/noRedeclare.js:4:13 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
✖ Shouldn't redeclare 'c'. Consider to delete it or rename it.
2 │ static {
3 │ var c = 3;
> 4 │ var c = 10;
│ ^
5 │ }
6 │ }
ℹ 'c' is defined here:
1 │ class C {
2 │ static {
> 3 │ var c = 3;
│ ^
4 │ var c = 10;
5 │ }
type Person = { name: string; }
class Person { name: string; }suspicious/noRedeclare.js:2:7 lint/suspicious/noRedeclare ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
✖ Shouldn't redeclare 'Person'. Consider to delete it or rename it.
1 │ type Person = { name: string; }
> 2 │ class Person { name: string; }
│ ^^^^^^
3 │
ℹ 'Person' is defined here:
> 1 │ type Person = { name: string; }
│ ^^^^^^
2 │ class Person { name: string; }
3 │
Valid
var a = 3;
a = 10;class Foo {
bar(a: A);
bar(a: A, b: B);
bar(a: A, b: B) {}
}