Métodos

Les comparto mis apuntes. 😄

¿Qué hacen los métodos?

Describen el comportamiento de los objetos.

Sintaxis

class nameClass {
		constructor (parameters) { statements }

		methodName (parameters: dataTypes): dataType { statements }
}

Mi solucion

export type formatDate = 'days' | 'months' | 'years';

class MyDate {
    year: number;
    month: number;
    day: number;
    leapYear: boolean = false; // by deafault the year is not leap year

    private _months: { [key: number]: string; } = {
        1: 'January',
        2: 'February',
        3: 'March',
        4: 'April',
        5: 'May',
        6: 'June',
        7: 'July',
        8: 'August',
        9: 'September',
        10: 'October',
        11: 'November',
        12: 'December'
    };

    private _month31: number[] = [1, 3, 5, 7, 8, 10, 12]; // list of months that have 31 days

    constructor(year: number, month: number, day: number) {
        this.year = this._validYear(year);
        this._leapYear()
        this.month = this._validMonth(month);
        this.day = this._validDay(day);
    }

    printFormat(format: string = 'dd / mm / yy'): string {
        if (this._validError() == null) { // if validError returns null then there are no errors
            format = format.replace('yy', this.year.toString());
            format = format.replace('dd', this.day.toString());
            format = format.replace('mm', this.month.toString());
            format = format.replace('mn', this._months[this.month]);
            return format;
        } else {
            return this._validError()!; // notation ! tells typescript that the programmer is in control
        }
    }

    private _validError(): string | null {
        // if any attribute has the value of zero then it is out of range and there is an error
        let error: string = '#outRange!'; // out of tange error indicator
        if (this.year == 0) {
            return `${error} year`; // error message
        }
        if (this.month == 0) {
            return `${error} month`; // error message
        }
        if (this.day == 0) {
            return `${error} day`; // error message
        }
        return null; // whithout errors
    }

    private _validYear(year: number) {
        // if the year is greater than zero it is valid
        if(year > 0) {
            return year;
        } else {
            return 0;
        }
    }

    private _validDay(day: number) {
        // validate the day
        if (day > 0) {
            if (this.month === 2) { // if the month is february
                let evaluateDay: number = 28;
                if (this.leapYear) { // if leap year
                    evaluateDay++;
                }
                if (day <= evaluateDay) {
                    return day;
                } else {
                    return 0;
                }
            } else { // if it is any month except february
                let evaluateDay: number = 30;
                if (this._month31.includes(this.month)) { // if the month has 31 days
                    evaluateDay++;
                }
                if (day <= evaluateDay) {
                    return day;
                } else {
                    return 0;
                }
            }
        } else {
            return 0
        }
    }

    private _validMonth(month: number) {
        // Validated that the month is between 1 and 12
        if (month > 0 && month < 13) {
            return month;
        } else {
            return 0;
        }
    }

    private _leapYear() {
        /**
         * @ Check if the year is a leap year
         */
        let result: number;
        result = (this.year / 4) % 2; // formula if ((n/4) % 2 == 0)

        if(result == 0) {
            this.leapYear = true;
        }
    }

    add(amount: number, format: formatDate) {
        if (this._validError() == null) {
            if (format == 'days') {
                for (let i = 0; i < amount; i++) {
                    this.day += 1;
                    if (this._validDay(this.day) == 0) { // Validated the day based on the month and year
                        /* if _validDay returns 0 the valid days for the current month
                        were exceeded then the month is increased and day is restarted */
                        this.month++;
                        if (this.month == 13) {
                            this.year++;
                            this.month = 1;
                        }
                        this.day = 1;
                    }
                }
            } else if (format == 'months') {
                for (let i = 0; i < amount; i++) {
                    this.month++;
                    if (this.month > 12) {
                        this.year++;
                        this.month = 1;
                    }
                }
            } else if (format == 'years') {
                if (amount > 0) {
                    this.year += amount;
                }
            }
        }
    }
}

const myDate = new MyDate(2000, 2, 29);
console.log(myDate.printFormat('dd of mn of yy'));
myDate.add(36, 'days');
console.log(myDate.printFormat());
myDate.add(40, 'months');
console.log(myDate.printFormat('mm - dd - yy'));

" Los metodos definen el comportamiento de los objetos."