typescript/no-unsafe-function-type Pedantic

What it does

Disallow using the unsafe built-in Function type.

Why is this bad?

TypeScript's built-in Function type allows being called with any number of arguments and returns type any. Function also allows classes or plain objects that happen to possess all properties of the Function class. It's generally better to specify function parameters and return types with the function type syntax.

Examples

Examples of incorrect code for this rule:

let noParametersOrReturn: Function;
noParametersOrReturn = () => {};

let stringToNumber: Function;
stringToNumber = (text: string) => text.length;

let identity: Function;
identity = (value) => value;

Examples of correct code for this rule:

let noParametersOrReturn: () => void;
noParametersOrReturn = () => {};

let stringToNumber: (text: string) => number;
stringToNumber = (text) => text.length;

let identity: <T>(value: T) => T;
identity = (value) => value;

References

• Rule Source