}
addMiddleware(
applyBeforeValidation: boolean,
global = true,
mutates = false
): YargsInstance {
argsert(
'<array|function> [boolean] [boolean] [boolean]',
[callback, applyBeforeValidation, global],
arguments.length
);
if (Array.isArray(callback)) {
for (let i = 0; i < callback.length; i++) {
if (typeof callback[i] !== 'function') {