Proxy Validator

gistfile1.txt

const rand = Math.random() < 0.5
const throwError = rand // random boolean 

// validation, error handling, boolean
let validator = {
    set: function(obj, prop, value) {
        if (prop === 'age') {
            if (!Number.isInteger(value)) {
                if (throwError) {
                    throw new TypeError('The age is not an integer')
                } else {
                    log('Age must be a number')
                }
                
            }
        if (value > 200) {
            if (throwError) {
                throw new RangeError('The age seems invalid')
            } else {
                log('Age must be a positive number')
            }
            
        }
        }

        // The default behavior to store the value
        obj[prop] = value

        // Indicate success
        return true
    }
}

let person = new Proxy({}, validator)

person.age = 100
console.log(person.age) // 100
person.age = 'young' // Throws an exception
person.age = 300 // Throws an exception