DefinitelyTyped/types/prompts/prompts-tests.ts

import prompts = require("prompts");

type HasProperty<T, K> = K extends keyof T ? true : false;

(async () => {
    const response = await prompts({
        type: "number",
        name: "value",
        message: "Input value to double:",
        validate: (value: any) => (value < 0 ? `Cant be less than zero` : true)
    });
    const HasPropValue: HasProperty<typeof response, "value"> = true;
    const DoesntHavePropAsdf: HasProperty<typeof response, "asdf"> = false;
})();

(async () => {
    await prompts([
        {
            type: 'text',
            name: 'language',
            message: "What langauge is the next greatest thing since sliced bread?",
        },
        {
            type: (prev, values) => {
                const HasPromptName: HasProperty<typeof values, "language"> = true;
                const DoesntHavePromptTypes: HasProperty<typeof values, "text"> = false;

                return prev === 'javascript' ? 'confirm' : null;
            },
            name: 'confirmation',
            message: "Have you tried TypeScript?"
        }
    ]);
})();