I mean it's the opposite of shift() , so if you're struggling to remember what it does, maybe that's a useful cognitive hook to hang it on? Answer from pookage on reddit.com
W3Schools
w3schools.com › jsref › jsref_unshift.asp
JavaScript Array unshift() Method
The unshift() method overwrites the original array. ... If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail: sales@w3schools.com · If you want to report an error, or if you want to make ...
SheCodes
shecodes.io › athena › 18575-difference-between-array-shift-and-array-unshift-in-javascript
[JavaScript] - Difference between array.shift() and | SheCodes
Learn how to use array.shift() and array.unshift() methods in JavaScript to manipulate elements in an array
Videos
01:40
Shift and Unshift Array Methods (in 1.5 min) - YouTube
12:11
YouTube
01:01
#javascript Important Array methods | pop, push, shift, unshift, ...
04:09
JavaScript Shift and Unshift Methods Explained - YouTube
06:17
JavaScript shift and unshift Method Complete JS Array Methods Series ...
MDN Web Docs
developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Global_Objects › Array › unshift
Array.prototype.unshift() - JavaScript | MDN
The unshift() method reads the length property of this. It shifts all indices in the range 0 to length - 1 right by the number of arguments (incrementing their values by this number). Then, it sets each index starting at 0 with the arguments passed to unshift().
CodingNomads
codingnomads.com › javascript-array-unshift-shift-pop-push
JavaScript Array Essentials: Using pop, push, shift, and unshift
Next, the shift() method is used, ... being performed on the array - one "shifts" elements out of the array, while the other "unshifts" or pushes elements into the array from the start....
Career Karma
careerkarma.com › blog › javascript › javascript shift and javascript unshift: a complete guide
JavaScript Shift and JavaScript Unshift: A Complete Guide
December 1, 2023 - This tutorial will explore how to use shift() and unshift() to remove and add items to the start of an array. In addition, we’ll walk through an example of each of these functions in a JavaScript program.
Medium
medium.com › an-idea › javascript-arrays-push-pop-shift-unshift-adc8fb815fc0
JavaScript Arrays: push(), pop(), shift() & unshift() | by Amanda M Johnson | An Idea (by Ingenious Piece) | Medium
October 10, 2021 - When working with arrays, it is important to understand the different types of methods and how they transform your data. push(), pop(), shift() and unshift() are only four of many other such methods. ... relies on the length property to know where to insert the new element(s) and will default to 0 if there is no length
Reddit
reddit.com › r/learnjavascript › who thought "unshift()" was a good name? why?
r/learnjavascript on Reddit: Who thought "unshift()" was a good name? Why?
December 20, 2023 -
EDIT: This is just venting, not confusion on how the word is technically used by JS :D
OK, this is why I keep starting and stopping learning JS- reserved words with extremely unrelated English meanings. "Unshift" means a previous shift occurred. That's the only meaning for it in English. But JS decided to use it as a prepend array method. Argh!!
That is all...
Top answer 1 of 23
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I mean it's the opposite of shift() , so if you're struggling to remember what it does, maybe that's a useful cognitive hook to hang it on?
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map has always annoyed me. It doesn't even display rail connections. edit: guys I know what map means in English, stop mansplaining. I still think it's a terrible choice.
MDN Web Docs
developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Global_Objects › Array › shift
Array.prototype.shift() - JavaScript | MDN
The shift() method shifts all values to the left by 1 and decrements the length by 1, resulting in the first element being removed.
Medium
omken.medium.com › javascripts-push-pop-shift-and-unshift-array-methods-with-respect-to-big-o-notation-e129ac5464
JavaScript’s Push, Pop, Shift, and Unshift Array Methods With Big O Notation. | by Omkesh B. Kendre | Medium
November 28, 2022 - The sample programming shown below will help you to understand the Big O complexities of the push(), pop(), shift(), and unshift() functions. let finalArray = []; finalArray.length = 10000000; var time1 = performance.now(); finalArray.push(1) var time2 = performance.now(); console.log(`Time calculated push(): ${(time2 - time1) / 1000} seconds.`) var time3 = performance.now(); finalArray.unshift(1) var time4 = performance.now(); console.log(`Time calculated unshift(): ${(time4 - time3) / 1000} seconds.`) var time5 = performance.now(); finalArray.pop() var time6 = performance.now(); console.log(`Time calculated pop(): ${(time6 - time5) / 1000} seconds.`) var time7 = performance.now(); finalArray.shift() var time8 = performance.now(); console.log(`Time calculated shift(): ${(time8 - time7) / 1000} seconds.`) /** Result: Time calculated push(): 0.012700000047683716 seconds.
Top answer 1 of 5
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As I known.
The shift command is come from the binary bit shift [1]. for Example.
001100
0 < 011000 // when you shift left
|
Yay!
I think it is quite simple it is just like you push it from behind. So this makes sense for me.
The unshift is the opposite way of shift.
001100
1 > 001100 // they called it unshift
1001100
|
Yay!
So that's it, Hope this helps!
[1] http://en.wikipedia.org/wiki/Bitwise_operation#Bit_shifts
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a.push(e) pushes e onto the end of a.
e = a.pop() pops the last element from a, to e.
a.unshift(e) enqueues e to the start of a.
e = a.shift() gets the first element from a to e.
Use push and pop for stacks.
Use unshift and pop for queues. (Or push and shift)
I remember the difference between shift (destructive) and unshift (constructive) simply by remembering that I use un-shift for en-queueing, and shift is the opposite to unshift.
Linux Hint
linuxhint.com › javascript-array-shift-and-unshift-method
JavaScript Array Shift and Unshift Method
Linux Hint LLC, [email protected] 1210 Kelly Park Circle, Morgan Hill, CA 95037 Privacy Policy and Terms of Use
Medium
developerchandan.medium.com › mastering-array-manipulation-in-javascript-exploring-pop-push-shift-unshift-splice-and-slice-c0ebaf3b004c
“Mastering Array Manipulation in JavaScript: Exploring pop, push, shift, unshift, splice, and slice Methods” | by Chandan Kumar | Medium
June 2, 2023 - 3. shift():-The shift() method removes the first element from an array and returns that element. let fruits = ['apple', 'banana', 'orange']; let removedFruit = fruits.shift(); console.log(removedFruit); // Output: 'apple' console.log(fruits); ...
TechBytes
mundrisoft.com › home › ui/ux development › javascript › javascript: what is the difference between shift() and unshift() array methods?
JavaScript: What is the difference between shift() and unshift() array methods?
April 11, 2019 - Definition: shift(): this method is use to remove first element of an array and returns new array. unshift(): this array method is used to add one or more arrays in existing array list and returns new array. usages of shift(): //JavaScript: ...
Reddit
reddit.com › r/learnjavascript › the four common javascript array methods push, pop, shift and unshift
r/learnjavascript on Reddit: The four common Javascript array methods Push, Pop, Shift and Unshift
May 16, 2020 -
Javascript has a number of methods related to arrays which allow programmers to perform various array operations. There are four methods which are particularly used for adding and removing elements to and from an array. They are: push(), pop(), shift() and unshift(). For an experienced as well as new programmers, its likely to sometimes get confused how each of them work and which one to use in which situation. Thus, in this article, we have tried to simplify the concept with pictures and examples. Let's start exploring them one by one. Then we will compare their similarities and differences. Please look at the pictures too for better understanding.
https://foxbits.dev/article/four-common-javascript-array-methods-push-pop-shift-and-unshift/15
Top answer 1 of 2
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Great article! I think it’s important to note that working with the end of the array (push/pop) is more performant than the beginning (shift/unshift). The reason for this is that the array is indexed, so adding to the end of the array doesn’t require any additional time. Shift/unshift though require the whole array to be reindexed since you’re adding to the beginning. Performance isn’t important while you’re learning, and really only matters with large arrays, but it is a good concept to get used to early on. In programming, that’s noted with something called big O notation, which is just a formalized way to loosely note what’s going on in the code. Push/pop are what’s known as O(1)—pronounced “O of 1”—which means that it’s constant time, or the time of the method will always take the same amount of time no matter the length of the array. Shift/unshift are O(n)—pronounced “O of n”—which means that the length of time it takes depends on the number of items in the array. This isn’t to say that shift/unshift are bad. They are useful! Use them as you will. Write first, and then optimize later.
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console.log([...["I", "dunno", "what", "you're"], "talking", "about"])
Bennadel
bennadel.com › blog › 1796-javascript-array-methods-unshift-shift-push-and-pop.htm
Javascript Array Methods: Unshift(), Shift(), Push(), And Pop()
April 21, 2020 - Javascript also has support for parallel methods that work on the beginning of the array, where the index is smallest. Unshift() and shift() are basically the same as push() and pop(), only, at the other end of the array.
DEV Community
dev.to › shubhamtiwari909 › array-method-in-js-shift-and-unshift-48bn
Array Method in JS - shift and unshift - DEV Community
September 5, 2022 - const array = [1,2,3,4,5]; const array2 = ["This","is","array2"] array.unshift(6) //single element insertion array.unshift(7,8,9) // multiple element insertion array.unshift("BOOTSTRAP5") // string element insertion array.unshift("TAILWINDCSS","REACT JS") //multiple string element insertion array.unshift([10,11]) // number array insertion array.unshift(["NODE JS","MONGO DB"]) // string array insertion array.unshift([[12,13],[14,15]]) // 2-d array insertion array.unshift({name:"shubham",age:21}) // Object insertion array.unshift(array2) // array stored in a variable then inserted array.unshift(undefined,null) // undefined and null insertion array.unshift(true,false) // Boolean insertion array.unshift(array) // [Circular *1] console.log(array) array.shift() // pop out the first element array.shift() // pop out the first element console.log("\n\nAfter shifting 2 times") console.log(array)
GeeksforGeeks
geeksforgeeks.org › javascript › what-is-the-difference-between-unshift-and-push-method-in-javascript
What is the difference between unshift() and Push() method in JavaScript? - GeeksforGeeks
July 23, 2025 - JavaScript Unshift() method is very much similar to the push() method but the difference is that the unshift() method adds the elements at the very beginning of the array whereas the push() method adds at the end of the array.
Reddit
reddit.com › r/learnprogramming › why are shift() and unshift() in js in the wrong order? i'm learning, but this seems very wrong.
r/learnprogramming on Reddit: Why are shift() and unshift() in JS in the wrong order? I'm learning, but this seems very wrong.
May 9, 2019 -
Shouldn't unshift() remove, and shift() add?
My train of thought is that "I will shift something into the beggining" and "unshift it from the beggining."
This makes no sense.
Yikes.
Top answer 1 of 5
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The only thing I can think is that "shift" is used in assembly language to mean "shift left" (roll moves right, in case you were wondering). So if you shift an array you slide everything over to the left. It's a pretty terrible name, IMHO. I'd do "pushfront" and "popfront", personally.
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shift comes from bit-shift which you do to a list of 1s and 0s. Regardless of what direction you shift you bump a bit off the list and a 0 comes in on the other side (the list size is fixed). So in js, shift means bump an item off the left end of the list which is like left-shift bit-shift. Pop is the name of the same operation for the right end of the list (that comes from stacks). So then unshift is just the opposite. Granted none of this makes it any less confusing :D
Suneet Agrawal
agrawalsuneet.github.io › blogs › array-operations-in-javascript-push-pop-shift-unshift
Array Operations in JavaScript (Push, Pop, Shift and Unshift) · Suneet Agrawal
We then use the shift() method to remove the first element from the array. The removed element is stored in the removedElement variable, and the resulting array has two elements. The unshift() method is used to add one or more elements to the beginning of an array.