no-unsafe-member-access
Disallow member access on a value with type
any.
Extending "plugin:@typescript-eslint/recommended-type-checked" in an ESLint configuration enables this rule.
This rule requires type information to run.
The any type in TypeScript is a dangerous "escape hatch" from the type system.
Using any disables many type checking rules and is generally best used only as a last resort or when prototyping code.
Despite your best intentions, the any type can sometimes leak into your codebase.
Accessing a member of an any-typed value creates a potential type safety hole and source of bugs in your codebase.
This rule disallows member access on any variable that is typed as any.
module.exports = {
"rules": {
"@typescript-eslint/no-unsafe-member-access": "error"
}
};
Try this rule in the playground ↗
Examples
- ❌ Incorrect
- ✅ Correct
declare const anyVar: any;
declare const nestedAny: { prop: any };
anyVar.a;
anyVar.a.b;
anyVar['a'];
anyVar['a']['b'];
nestedAny.prop.a;
nestedAny.prop['a'];
const key = 'a';
nestedAny.prop[key];
// Using an any to access a member is unsafe
const arr = [1, 2, 3];
arr[anyVar];
nestedAny[anyVar];
declare const properlyTyped: { prop: { a: string } };
properlyTyped.prop.a;
properlyTyped.prop['a'];
const key = 'a';
properlyTyped.prop[key];
const arr = [1, 2, 3];
arr[1];
let idx = 1;
arr[idx];
arr[idx++];
Options
This rule is not configurable.
When Not To Use It
If your codebase has many existing anys or areas of unsafe code, it may be difficult to enable this rule.
It may be easier to skip the no-unsafe-* rules pending increasing type safety in unsafe areas of your project.
You might consider using ESLint disable comments for those specific situations instead of completely disabling this rule.
Related To
Type checked lint rules are more powerful than traditional lint rules, but also require configuring type checked linting.
See Troubleshooting > Linting with Type Information > Performance if you experience performance degredations after enabling type checked rules.