Code-test-question-solved.js

function changeDateFormat(dates) {
    // Write the code that goes here
    const regExp = /^\d{2,4}(\/|-)\d{2}(\/|-)\d{2,4}$/
    const regExpG = /(-|\/)/
    const newArr = [];
    for (let i = 0; i < dates.length; i++) {
        if(dates[i].match(regExp)===null){
            break;
        } else if (dates[i].match(regExp).length > 0) {
            newArr.push(
                fixFormat(
                    dates[i], 
                    regExpG.exec(dates[i])[0], 
                    regExpG.exec(dates[i]).index)
            )
        }
    }
    function fixFormat(date, splitter, firstPos) {
        const spl = date.split(splitter);
        if(splitter==='-' && firstPos===2){
            return `${spl[2]}${spl[0]}${spl[1]}`
        } else if (splitter==='/' && firstPos===2){
            return `${spl[2]}${spl[1]}${spl[0]}`
        } else if(splitter==='/' && firstPos===4){
            return spl.join('');
        }
    }
    return newArr
}

var dates = changeDateFormat(["2010/03/30", "15/12/2016", "11-15-2012", "20130720"]);
for (index = 0; index < dates.length; ++index) {
    console.log(dates[index]);
}