noDelete

Invalid

const arr = [['a','b','c'], [1, 2, 3]];
delete arr[0][2];

warning[noDelete]: This is an unexpected use of the delete operator.
  ┌─ noDelete.js:2:1
  │
2 │ delete arr[0][2];
  │ ----------------

Suggested fix: Replace with undefined assignment
    | @@ -1,2 +1,2 @@
0 0 |   const arr = [['a','b','c'], [1, 2, 3]];
1   | - delete arr[0][2];
  1 | + arr[0][2] = undefined;

const obj = {a: {b: {c: 123}}};
delete obj.a.b.c;

warning[noDelete]: This is an unexpected use of the delete operator.
  ┌─ noDelete.js:2:1
  │
2 │ delete obj.a.b.c;
  │ ----------------

Suggested fix: Replace with undefined assignment
    | @@ -1,2 +1,2 @@
0 0 |   const obj = {a: {b: {c: 123}}};
1   | - delete obj.a.b.c;
  1 | + obj.a.b.c = undefined;

Valid

const foo = new Set([1,2,3]);
foo.delete(1);