Disallows using a non-null assertion in the left operand of the nullish coalescing operator.
The nullish coalescing operator is designed to provide a default value when dealing with null
or undefined
.
Using non-null assertions in the left operand of the nullish coalescing operator is redundant.
Examples of code for this rule:
/* eslint @typescript-eslint/no-non-null-asserted-nullish-coalescing: "error" */
foo! ?? bar;
foo.bazz! ?? bar;
foo!.bazz! ?? bar;
foo()! ?? bar;
let x!: string;
x! ?? '';
let x: string;
x = foo();
x! ?? '';
/* eslint @typescript-eslint/no-non-null-asserted-nullish-coalescing: "error" */
foo ?? bar;
foo ?? bar!;
foo!.bazz ?? bar;
foo!.bazz ?? bar!;
foo() ?? bar;
// This is considered correct code because there's no way for the user to satisfy it.
let x: string;
x! ?? '';
If you are not using TypeScript 3.7 (or greater), then you will not need to use this rule, as the nullish coalescing operator is not supported.
- ✅ Recommended
- 🔧 Fixable
- 💭 Requires type information