function?log(target)?{
????const?desc?=?Object.getOwnPropertyDescriptors(target.prototype)

????for?(const?key?of?Object.keys(desc))?{
????????if?(key?===?'constructor')?{
????????????continue
????????}

????????const?func?=?desc[key].value

????????if?('function'?===?typeof?func)?{
????????????Object.defineProperty(target.prototype,?key,?{
????????????????value(...args)?{
????????????????????console.log('before?'?+?key)
????????????????????const?ret?=?func.apply(this.args)
????????????????????console.log('after?'?+?key)

????????????????return?ret
????????????????}
????????????})
????????}
????}
}

function?readonly(target,?key,?descriptor)?{
????descriptor.writable?=?false
}

function?validate(target,?key,?descriptor)?{
????const?func?=?descriptor.value
????descriptor.value?=?function(...args)?{
????????console.log(args)
????????for?(let?num?of?args)?{
????????????if?('number'?!==?typeof?num)?{
????????????????throw?new?Error(`"${num}"?is?not?a?number`)
????????????}
????????}

????????return?func.apply(this,?args)
????}
}


@log
class?Numberic{
????@readonly?PI?=?3.1415926;


????@validate
????add(...nums){
????????return?nums.reduce((p,?n)?=>?(p?+?n),?0)
????}
}

new?Numberic().add(1,'x')