const ALL_LOWER_REGEXP = /^[^A-Z]*$/;
function otherConditions(input) {
return true;
}
function allLowerCase(input) {
return ALL_LOWER_REGEXP.test(input);
}
function isValidInput(input, allowUppercase = false) {
return (allowUppercase || allLowerCase(input)) && otherConditions(input);
}
isValidInput('aaaa', true)
// console.assert(isValidInput('asdasd', false), 'input contains uppercase but allowUppercase = false')