@yobta/validator/lib/constant/constant.js

Tree-shakable es6 validator

import { rule } from '../rule/rule.js';
export const constantMessage = (value) => `Should be identical to "${String(value)}"`;
export function constant(value, message) {
    return rule((input = '') => {
        // @ts-ignore
        if (input === value) {
            return value;
        }
        if (input === '') {
            return undefined;
        }
        throw new Error(message !== null && message !== void 0 ? message : constantMessage(value));
    });
}