Use function types instead of interfaces with call signatures (prefer-function-type)

Rule Details

This rule suggests using a function type instead of an interface or object type literal with a single call signature.

Examples of incorrect code for this rule:

interface Foo {
  (): string;
}

function foo(bar: { (): number }): number {
  return bar();
}

interface Foo extends Function {
  (): void;
}

Examples of correct code for this rule:

interface Foo {
  (): void;
  bar: number;
}

function foo(bar: { (): string; baz: number }): string {
  return bar();
}

interface Foo {
  bar: string;
}
interface Bar extends Foo {
  (): void;
}

If you specifically want to use an interface or type literal with a single call signature for stylistic reasons, you can disable this rule.