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consistent-generic-constructors

Enforce specifying generic type arguments on type annotation or constructor name of a constructor call.

When constructing a generic class, you can specify the type arguments on either the left-hand side (as a type annotation) or the right-hand side (as part of the constructor call):

// Left-hand side
const map: Map<string, number> = new Map();

// Right-hand side
const map = new Map<string, number>();

This rule ensures that type arguments appear consistently on one side of the declaration.

Attributes

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

Rule Details​

The rule never reports when there are type parameters on both sides, or neither sides of the declaration. It also doesn't report if the names of the type annotation and the constructor don't match.

.eslintrc.cjs
module.exports = {
  "rules": {
    "@typescript-eslint/consistent-generic-constructors": "warn"
  }
};

Options​

This rule accepts an options string of the following possible values:

type Options = "type-annotation" | "constructor";

const defaultOptions: Options = ["constructor"];
  • constructor (default): type arguments that only appear on the type annotation are disallowed.
  • type-annotation: type arguments that only appear on the constructor are disallowed.

constructor​

const map: Map<string, number> = new Map();
const set: Set<string> = new Set();

type-annotation​

const map = new Map<string, number>();
const set = new Set<string>();

When Not To Use It​

You can turn this rule off if you don't want to enforce one kind of generic constructor style over the other.

Resources​