Show Yesterday and Today's date together javascript

Question

I want to display yesterday's date and Today's date simultaneously on my Dashboard in a . For eg if today's date is 30 june 2019 , it should show 29 june 2019 as yesterday or if today's date is 1 july 2019 , it should display 30 june 2019 as yesterday date .

I tried calculating the previous day and date on the basis of today's date but it not changing everytime automatically. I got stuck in the looping functions.

getToday(){

        const monthNames = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];


        var dateToday = new Date().getDate();
        let monthToday = monthNames[new Date().getMonth()];
        let yearToday = new Date().getFullYear();

    }


getYesterday(){
    // var dateToday = new Date().getDate();
    //let dateYesterday = new Date(Date.now() - 86400000).getDate();
    //let monthYesterday = new Date(Date.now() - 86400000).getMonth();
    //console.log(dateYesterday,monthYesterday)



   //another approach I tried following
   var dateToday = new Date().getDate();
   var yesterday = dateToday.setDate(dateToday.getDate() - 1);
}

componentDidMount(){

            this.getToday();
            this.getYesterday();
}

Please help to complete this.

Answer 1

You need:

var d = new Date();
d.setDate(d.getDate() -1);

d has the yesterday date.

getFullYear()   Get the year as a four digit number (yyyy)
getMonth()  Get the month as a number (0-11)
getDate()   Get the day as a number (1-31)
getHours()  Get the hour (0-23)
getMinutes()    Get the minute (0-59)
getSeconds()    Get the second (0-59)
getMilliseconds()   Get the millisecond (0-999)
getTime()   Get the time (milliseconds since January 1, 1970)
getDay()    Get the weekday as a number (0-6)
Date.now()  Get the time. ECMAScript 5.

Example:

var d = new Date();
d.setDate(d.getDate() -1);
monthYesterday = d.getMonth(); // you get the month of yesterday
yearYesterday = d.getFullYear(); // you get the year of yesterday (format yyyy)

Answer 2

Here's an working example; I've simplified getToday as well.

https://jsfiddle.net/f0pwhj3L/9/

getToday(){
        var dateToday = new Date();
        const month = dateToday.toLocaleString('en-us', { month: 'long' });        
    }


getYesterday(){
   const dateYesterday = new Date();
   dateYesterday.setDate(-1);
   const dayYesterday = dateYesterday.getDate();
   const monthYesterday = dateYesterday.getMonth();

}

componentDidMount(){

            this.getToday();
            this.getYesterday();
}