How to dynamically change the key names of object properties in an array

Question

I have an array of objects, like so:

arr = [{"timeslot":"6am7am","AVG(Monday)":10,"AVG(Tuesday)":11,"AVG(Wednesday)":7}]

Each object will always contain the "timeslot" property, and can contain any combination of the day-of-the-week properties, Monday through Sunday. Each day of the week may only be represented once in a single object.

I want to alter each object: specifically, the key names of the day-of-the-week properties only (the "timeslot" property will be unchanged"), to get an array like so:

newArr = [{"timeslot":"6am7am","Monday":10,"Tuesday":11,"Wednesday":7}]

My slightly unreadable solution works:

// Iterate the array of objects results.forEach(function(o) { // Iterate the object's properties Object.keys(o).forEach(function(k) { if(k.includes("AVG")) { var len = k.length; var pos = len - 1; var newKey = k.slice(4, pos); // Extract the day of the week from the key name o[newKey] = o[k]; // Create the new property with the same value and the new key-name delete o[k]; // Delete the original property } }); });

How can I improve this solution?

You could just write o[k.slice(4, -1)] = o[k]. No need for all those intermediate variables. There is not much else that could be improved. — Felix Kling
– Felix Kling, Commented Jan 13, 2017 at 14:56

Ori Drori · Accepted Answer · 2017-01-13 15:02:22Z

Instead of mutating the original array by adding and removing keys from each object, Array#map the array into a new array, and recreate the objects using Array#reduce:

var arr = [{"timeslot":"6am7am","AVG(Monday)":10,"AVG(Tuesday)":11,"AVG(Wednesday)":7}]; var result = arr.map(function(obj) { return Object.keys(obj).reduce(function(r, key) { var k = key.includes('AVG') ? key.slice(4, -1) : key; r[k] = obj[key]; return r; }, {}); }); console.log(result);

Collectives™ on Stack Overflow

How to dynamically change the key names of object properties in an array

1 Answer 1

Comments

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Related