.toReversed()

The toReversed() method returns a new array in which the order of all elements is reversed compared to the original array: the first element becomes the last, and the last becomes the first.

        
          
          const planets = ['Mercury', 'Venus', 'Earth', 'Mars']const reversedPlanets = planets.toReversed()console.log(reversedPlanets)// ['Mars', 'Earth', 'Venus', 'Mercury']// The original array remains unchangedconsole.log(planets)// ['Mercury', 'Venus', 'Earth', 'Mars']
          const planets = ['Mercury', 'Venus', 'Earth', 'Mars']
const reversedPlanets = planets.toReversed()
console.log(reversedPlanets)
// ['Mars', 'Earth', 'Venus', 'Mercury']

// The original array remains unchanged
console.log(planets)
// ['Mercury', 'Venus', 'Earth', 'Mars']

        
        
          
            
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Array.toReversed() has no arguments.

Array.toReversed() returns a new array in which the order of all elements is reversed compared to the original array.

Arrays already have the reverse() method to obtain an array with the elements in reverse order. Unlike it, the toReversed() method does not modify the original array.

Let's practice with cats:

        
          
          const cats = ['Murka', 'Kuzya', 'Murr', 'Cheshire Cat']console.log(cats.toReversed())// ['Cheshire Cat', 'Murr', 'Kuzya', 'Murka']// The original array remains unchangedconsole.log(cats)// ['Murka', 'Kuzya', 'Murr', 'Cheshire Cat']
          const cats = ['Murka', 'Kuzya', 'Murr', 'Cheshire Cat']
console.log(cats.toReversed())
// ['Cheshire Cat', 'Murr', 'Kuzya', 'Murka']

// The original array remains unchanged
console.log(cats)
// ['Murka', 'Kuzya', 'Murr', 'Cheshire Cat']

        
        
          
            
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When using the reverse() method, the original array is also modified:

        
          
          const cats = ['Murka', 'Kuzya', 'Murr', 'Cheshire Cat']console.log(cats.reverse())// ['Cheshire Cat', 'Murr', 'Kuzya', 'Murka']// The original array has changed!console.log(cats)// ['Cheshire Cat', 'Murr', 'Kuzya', 'Murka']
          const cats = ['Murka', 'Kuzya', 'Murr', 'Cheshire Cat']
console.log(cats.reverse())
// ['Cheshire Cat', 'Murr', 'Kuzya', 'Murka']

// The original array has changed!
console.log(cats)
// ['Cheshire Cat', 'Murr', 'Kuzya', 'Murka']

        
        
          
            
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If the elements of the original array are objects, the array returned by the toReversed() method will contain references, not new objects. Thus, changes to an object in the original array will be visible in the created array and vice versa:

        
          
          const versions = [  {name: 'ES6'}, {name:'ES2016'}, {name: 'ES2017'}]const result = versions.toReversed()console.log(result)// [{ name: 'ES2017'}, {name: 'ES2016'}, {name: 'ES6'}]// Change an element of the original arrayversions[0].year = 2015console.log(versions)// [{name: 'ES6', year: 2015}, {name: 'ES2016'}, {name: 'ES2017'}]// Changes are also visible in the created arrayconsole.log(result)// [{ name: 'ES2017'}, {name: 'ES2016'}, {name: 'ES6', year: 2015}]
          const versions = [
  {name: 'ES6'}, {name:'ES2016'}, {name: 'ES2017'}
]
const result = versions.toReversed()
console.log(result)
// [{ name: 'ES2017'}, {name: 'ES2016'}, {name: 'ES6'}]

// Change an element of the original array
versions[0].year = 2015

console.log(versions)
// [{name: 'ES6', year: 2015}, {name: 'ES2016'}, {name: 'ES2017'}]

// Changes are also visible in the created array
console.log(result)
// [{ name: 'ES2017'}, {name: 'ES2016'}, {name: 'ES6', year: 2015}]

        
        
          
            
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You can read more about the peculiarities of object copying in the article “Shallow and Deep Copying of Elements”.

💡 If the array has unfilled elements, toReversed() will return undefined as the value for all unfilled elements:

        
          
          const poets = ['Emily Dickinson']poets[3] = 'Robert Frost'console.log(poets)// ['Emily Dickinson', <2 empty items>, 'Robert Frost']console.log(poets.toReversed())// ['Robert Frost', undefined, undefined, 'Emily Dickinson']
          const poets = ['Emily Dickinson']
poets[3] = 'Robert Frost'

console.log(poets)
// ['Emily Dickinson', <2 empty items>, 'Robert Frost']

console.log(poets.toReversed())
// ['Robert Frost', undefined, undefined, 'Emily Dickinson']

        
        
          
            
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💡 Support for the toReversed() method in major browsers and in Node.js appeared relatively recently. For example, trying to use toReversed() in Node.js v.18.19.0 will lead to an error:

        
          
          try {console.log([1, 2, 3].toReversed())} catch (err) {  console.log('Caught an error! Here it is: ', err.message)}// Caught an error!// Here it is: [1,2,3].toReversed is not a function
          try {
console.log([1, 2, 3].toReversed())
} catch (err) {
  console.log('Caught an error! Here it is: ', err.message)
}
// Caught an error!
// Here it is: [1,2,3].toReversed is not a function

        
        
          
            
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