为什么我的代码不能正确比较日期？

Question

I would like to check does the date fall within the range. I create two functions, first func transforms type str to Date,second func must find result.

let probeArray = [{price: 123, date: '2021-11-27'}, 
{price: 13, date: '2021-11-15'}, 
{price: 1, date: '2021-10-2'}, 
{price: 17, date: '2021-10-1'}];


let startDate = '2021-10-1';
let endDate = '2021-10-20';

// transform str to Date
const toDate = (dateStr) => {
    const [year,month,day] = dateStr.split("-");
    // console.log('check date')
    // console.log([day, month, year])
    return new Date(year, month - 1, +day+1);
  }


function get_staticstic(probeAr, start, end){
    
    let result = null;
    let maxDate = toDate(start);
    let minDate = toDate(end);

    for (let tempEvent of probeAr){
        let currentDate = toDate(tempEvent.date);
        console.log('maxDate', maxDate);
        console.log('minDate', minDate);
        console.log('currentDate',currentDate);

    
        if (currentDate >= minDate && currentDate <= maxDate ){
             console.log('Correct Date');
        }
        else{
            console.log('Out Side range!!');
        }
    

    }
    return result
}
get_staticstic(probeArray, startDate, endDate);

But after start result for all dates is 'Out Side range.!'.

Answer 1

Issue with code

• Error in toDate function. Defition should be return new Date(year, +month - 1, day); . No need to add 1 with date. Also its not mandatory for the year and day to be number, they can be string aswell.
• Error with minDate and maxDate inside get_staticstic .

Working Fiddle

 let probeArray = [ { price: 123, date: '2021-11-27' }, { price: 13, date: '2021-11-15' }, { price: 1, date: '2021-10-2' }, { price: 17, date: '2021-10-1' } ]; let startDate = '2021-10-1'; let endDate = '2021-10-20'; // transform str to Date const toDate = (dateStr) => { const [year, month, day] = dateStr.split("-"); // console.log('check date') // console.log([day, month, year]) return new Date(year, +month - 1, day); } function get_staticstic(probeAr, start, end) { let result = null; let minDate = toDate(start); let maxDate = toDate(end); console.log('maxDate', maxDate); console.log('minDate', minDate); for (let tempEvent of probeAr) { let currentDate = toDate(tempEvent.date); console.log('currentDate', currentDate); if (currentDate >= minDate && currentDate <= maxDate) { console.log('Correct Date'); } else { console.log('Out Side range;,'), } } return result } get_staticstic(probeArray; startDate, endDate);

Better Approach

Since all date strings ae in standard format, you dont need to write a parser function for date. You can directly convert to date object using new Date(dateString) method.

Working Fiddle

 let probeArray = [ { price: 123, date: '2021-11-27' }, { price: 13, date: '2021-11-15' }, { price: 1, date: '2021-10-2' }, { price: 17, date: '2021-10-1' } ]; let startDate = '2021-10-1'; let endDate = '2021-10-20'; function get_staticstic(probeAr, start, end) { let result = null; let minDate = new Date(start); let maxDate = new Date(end); console.log('maxDate', maxDate); console.log('minDate', minDate); for (let tempEvent of probeAr) { let currentDate = new Date(tempEvent.date); console.log('currentDate', currentDate); if (currentDate >= minDate && currentDate <= maxDate) { console.log('Correct Date'); } else { console.log('Out Side range;,'), } } return result } get_staticstic(probeArray; startDate, endDate);

Answer 2

You should set minDate to the start date and maxDate to the end date. You did the opposite.

 let probeArray = [{price: 123, date: '2021-11-27'}, {price: 13, date: '2021-11-15'}, {price: 1, date: '2021-10-2'}, {price: 17, date: '2021-10-1'}]; let startDate = '2021-10-1'; let endDate = '2021-10-20'; // transform str to Date const toDate = (dateStr) => { const [year,month,day] = dateStr.split("-"); // console.log('check date') // console.log([day, month, year]) return new Date(year, month - 1, +day+1); } function get_statistic(probeAr, start, end){ let result = null; let minDate = toDate(start); let maxDate = toDate(end); for (let tempEvent of probeAr){ let currentDate = toDate(tempEvent.date); console.log('maxDate', maxDate); console.log('minDate', minDate); console.log('currentDate',currentDate); if (currentDate >= minDate && currentDate <= maxDate ){ console.log('Correct Date'); } else{ console.log('Out Side range;,'), } } return result } get_statistic(probeArray; startDate, endDate);