Sorting objects according to days name JavaScript

Let’s say, we have an array of objects that contains data about the humidity over the seven days of a week. The data, however, sits randomly in the array right now. We are supposed to sort the array of objects according to the days like data for Monday comes first, then Tuesday, Wednesday and lastly Sunday.

Following is our array −

const weather = [{
   day: 'Wednesday',
   humidity: 60
}, {
   day: 'Saturday',
   humidity: 50
}, {
   day: 'Thursday',
   humidity: 65
}, {
   day: 'Monday',
   humidity: 40
}, {
   day: 'Sunday',
   humidity: 35
}, {
   day: 'Friday',
   humidity: 80
}, {
   day: 'Tuesday',
   humidity: 45
}];

The key to this problem is creating our map object that maps the specific days of the week to their correct indices. It would look something like this −

const map = {
   'Monday': 1,
   'Tuesday': 2,
   'Wednesday': 3,
   'Thursday': 4,
   'Friday': 5,
   'Saturday': 6,
   'Sunday': 7
};

Now with this clear, we can apply the Array.prototype.sort() method passing in a custom callback that ranks the object according to their index in map.

The full code for this will be −

Example

const weather = [{
   day: 'Wednesday',
   humidity: 60
}, {
   day: 'Saturday',
   humidity: 50
}, {
   day: 'Thursday',
   humidity: 65
}, {
   day: 'Monday',
   humidity: 40
}, {
   day: 'Sunday',
   humidity: 35
}, {
   day: 'Friday',
   humidity: 80
}, {
   day: 'Tuesday',
   humidity: 45
}];
const map = {
   'Monday': 1,'Tuesday': 2,'Wednesday': 3,'Thursday': 4,'Friday': 5,'Saturday': 6,
   'Sunday': 7
};
weather.sort((a, b) => {
   return map[a.day] - map[b.day];
});
console.log(weather);

Output

The output for this code will be −

[
   { day: 'Monday', humidity: 40 },
   { day: 'Tuesday', humidity: 45 },
   { day: 'Wednesday', humidity: 60 },
   { day: 'Thursday', humidity: 65 },
   { day: 'Friday', humidity: 80 },
   { day: 'Saturday', humidity: 50 },
   { day: 'Sunday', humidity: 35 }
]

AmitDiwan

e

Updated on: 19-Aug-2020

2K+ Views

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