no-return-void.md

Disallow returning nothing (no-return-void)

Disallow functions that are declared as returning nothing.

Rule Details

In functional programming functions must return something, they cannot return nothing.

By default, this rule allows function to return undefined and null.

Note: For performance reasons, this rule does not check implicit return types. We recommend using the rule @typescript-eslint/explicit-function-return-type in conjunction with this rule.

Examples of incorrect code for this rule:

/* eslint functional/no-return-void: "error" */

function updateText(): void {

}

Examples of correct code for this rule:

/* eslint functional/no-return-void: "error" */

function updateText(value: string): string {

}

Options

This rule accepts an options object of the following type:

{
  allowNull: boolean;
  allowUndefined: boolean;
  ignoreImplicit: boolean;
}

The default options:

{
  allowNull: true,
  allowUndefined: true,
  ignoreImplicit: false,
}

allowNull

If true allow returning null.

allowUndefined

If true allow returning undefined.

ignoreImplicit

If true ignore functions that don't explicitly specify a return type.