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no-non-null-asserted-nullish-coalescing

Disallows non-null assertions in the left operand of a nullish coalescing operator.

Attributes

  • Included in configs
    • ✅ Recommended
    • 🔒 Strict
  • Fixable
    • 🔧 Automated Fixer
    • 🛠 Suggestion Fixer
  • 💭 Requires type information

Rule Details​

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! ?? '';

Options​

// .eslintrc.json
{
  "rules": {
    "@typescript-eslint/no-non-null-asserted-nullish-coalescing": "warn"
  }
}

This rule is not configurable.

When Not To Use It​

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.

Further Reading​