Group array Elements in a sequence JavaScript

Question

I am trying to group weekdays together based on the property value in an array. I have used lodash to obtain a solution. My code looks like this,

const array = [{
    weekDay: 'Monday',
    hoursInfo: '11:00am-8:00pm',
  },
  {
    weekDay: 'Tuesday',
    hoursInfo: '11:00am-8:00pm',
  },
  {
    weekDay: 'Wednesday',
    hoursInfo: '9:00am-11:00am',
  },
  {
    weekDay: 'Thursday',
    hoursInfo: '11:00am-8:00pm',
  },
  {
    weekDay: 'Friday',
    hoursInfo: '11:00am-9:00pm',
  },
  {
    weekDay: 'Saturday',
    hoursInfo: '11:00am-9:00pm',
  },
  {
    weekDay: 'Sunday',
    hoursInfo: 'Closed',
  },
];
const result = _.chain(array).groupBy("hoursInfo").value();
document.getElementById("result").innerHTML = JSON.stringify(result);

<script src="https://cdn.jsdelivr.net/npm/[email protected]/lodash.min.js"></script>
<div id="result"></div>

I am able to group the list of weekdays which has the same timings together, but my requirement is to group them in a sequence. My expected output is something like this,

Monday-Tuesday: 11:00am-8:00pm
Wedesday: 9:00am-11:00am
Thursday: 11:00am-8:00pm
Friday-Saturday: 11:00am-9:00pm
Sunday: Closed

Please help me with a better approach

Answer 1

This solution should work, let me know if you need explanations :)

Edit: for some reasons i can't comment on mplungjan's answer but his solution won't work if there are more than two consecutives days with the same hoursInfo. Try to replace wednesday's hours by "11:00am-8:00pm" and you will get : 'Monday- Tuesday- Wednesday- Thursday: 11:00am-8:00pm'

const array = [{weekDay:"Monday",hoursInfo:"11:00am-8:00pm"},{weekDay:"Tuesday",hoursInfo:"11:00am-8:00pm"},{weekDay:"Wednesday",hoursInfo:"9:00am-11:00am"},{weekDay:"Thursday",hoursInfo:"11:00am-8:00pm"},{weekDay:"Friday",hoursInfo:"11:00am-9:00pm"},{weekDay:"Saturday",hoursInfo:"11:00am-9:00pm"},{weekDay:"Sunday",hoursInfo:"Closed"}];

const getHours = (array) => {

    let results = [];

    array.forEach((element, index) => {
        if(index === 0) return results.push([element.weekDay, element.hoursInfo]);

        if(element.hoursInfo === results[results.length - 1][1]) {
            const current = results[results.length - 1][0];
            results[results.length - 1][0] = `${current.split('-')[0]}-${element.weekDay}`;
        }
        else {
            results.push([element.weekDay, element.hoursInfo]);
        }
    })

    return results.map(element => `${element[0]}: ${element[1]}`).join('\n');
}


console.log(getHours(array));