TypeScript has a powerful system to deal with null or undefined values. In JavaScript, people are confused about null and undefined as both look like absence of value. What is the difference between null and undefined in JavaScript? This snippet will guide you in finding the ways of checking whether the string is empty, undefined, or null. Both undefined and null are falsy by default. In this article, I will attempt to break down the documentation for null and undefined in JavaScript and explain exactly what they mean in plain English. Besides, when a function doesn't return a value, it returns undefined. Best wishes, John. The == dont require same types and made implicit conversion before comparison (using .valueOf() and .toString()). null !== undefined . Any . Note that in older JS versions, undefined isn't a keyword the way null is. We have heard the word "null" many times in English. Thus, accessing player.name will results in undefined. let hasCat = null; // nullish The same meaning is analogous to the meaning of null in programming. Would like to stay longer than 90 days. How do I put three reasons together in a sentence? Null means an empty value or a blank value. Null essentially represents a non-existent or an empty value i.e. Therefore, JavaScript refers to it as undefined. However, when we use the strict equality (===) to compare null and undefined, it returns false. An undefined data type is a variable that is declared using either var or let that is not yet assigned to a value. 1. In this tutorial, you will learn about these two keywords. Can several CRTs be wired in parallel to one oscilloscope circuit? Null is a data type that has the sole value null. The undefined property indicates that a variable has not been assigned a value, or not declared at all. Introduction. Why is (null==undefined) true in JavaScript? But if you then assign a = null; then a will now be null. In Java null is used to show absence of value. While performing various arithmetic operations, null is converted to 0, and then the operation is performed, while undefined is converted to NaN. @AndyE: at this point, I don't believe any browser is fully ES5 compliant, which is why I didn't mention any specific browsers. undefined JavaScript. undefined is the more generic one, used as the default value of variables until they're assigned some other value, as the value of function arguments that weren't provided when the function was called, and as the value you get when you ask an object for a property it doesn't have. The NaN property represents a "Not-a-Number" value. If both operands are null or both operands are undefined, return true. PSE Advent Calendar 2022 (Day 11): The other side of Christmas. Those two are the following. As for the equal == and strictly equal === comparators, the first one is weakly type, while strictly equal also checks for the type of values. All Languages >> Javascript >> null javascript w3schools "null javascript w3schools" Code Answer. Here's a summary: How do I check a variable if it's null or undefined. This conversion can be verified using the following code snippet. and what is the difference between the null and undefined? [js]var v1= 5+ null; console.log (v1) [/js] Upon execution, this output of this code will print 5. Let's have a quick look at this. undefined. Many people consider it a bug in JavaScript as it considers null as an object. GoogleJavaScriptDartnullundefined!. In JavaScript an undefined variable is a variable that as never been declared, or never assigned a value. How do I include a JavaScript file in another JavaScript file? Checks the value and datatype should be same . . (Do not feel badly if youre not sure what this means. This is because, under the hood, JavaScript recognizes both of them as empty. check for properties on an existing object if (my_obj.foo == null) {.} Fortunately, JavaScript offers a bunch of ways to determine if the object has a specific property: obj.prop !== undefined: compare against undefined directly. If you change it to null, then yes. What happens if you score more than 99 points in volleyball? A variable will only return nullif a programmer or an API. But since EcmaScript-5 is out, this has been disallowed, and even though it is still a property of the global object, it has been made non-writable now. .css-y5tg4h{width:1.25rem;height:1.25rem;margin-right:0.5rem;opacity:0.75;fill:currentColor;}.css-r1dmb{width:1.25rem;height:1.25rem;margin-right:0.5rem;opacity:0.75;fill:currentColor;}2 min read, Subscribe to my newsletter and never miss my upcoming articles. Null used for intentionally missing values. Method 1: By using equality operator: We can use equlity operator, == with null or undefined to check if an object is either null or undefined. That means that 0 == "0" will return true; while 0 === "0" will return false, because a number is not a string. What is difference between undefined and null in javascript and what are their usecases? The type will also be undefined. If either operand is NaN, return false. Undefined, on the other hand, means the variable has been declared, but its value has not been assigned. The player object has no name property. In which case you may do: If you omit the optional parameter doSomething(1, 2) thenoptional will be the "three" string but if you pass doSomething(1, 2, null) then optional will be null. Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. Where does the idea of selling dragon parts come from? As you can see so far, null and undefined are different, but share some similarities. You can check this using the typeof operator. just check if a variable has a valid value like this : it will return true if variable does't contain : It means the variable is not yet intialized . 2. javascript by SAMER SAEID on May 20 2022 Comment . The properties describe the dog object. So does the optional chaining operator ( ?. Here you have all (src): If your (logical) check is for a negation (!) In this tutorial, we'll discuss undefined in JavaScript. The rest of this page applies for when strictNullChecks is enabled. Is there a standard function to check for null, undefined, or blank variables in JavaScript? So, yes, there's a difference. In these cases, they'll try to coerce the values, unsuccessfully. Try With Different Logic. Undefined means a variable that has been declared, but the value of that variable has not yet been assigned. 1. "If two operands are of the same type and value, then === produces true and !== produces false." By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. The === check values and types. What is the correct way to check for string equality in JavaScript? It is one of the primitive values of JavaScript. It only check value is equals not datatype . And similarly, the DOM's getElementById operation returns an object reference either a valid one (if it found the DOM element), or null (if it didn't). The undefined data type is not as complicated as the null data type. null undefined javascript Code Example Undefined used for unintentionally missing values. A primitive value in JavaScript is immutable, meaning the value cannot be changed. @AndyE - thanks for the heads up. That's all folks! So basically, it is a data type. This is so because while performing arithmetic operations, the function toNumber() gets called on it, which converts null to 0 and undefined to NaN. Its initial value is the primitive undefined. Hello there! 'Null' is a keyword in JavaScript that signifies 'no value' or nonexistence of any value. For example, var demo; alert (demo); //shows undefined alert (typeof demo); //shows undefined. I start learning how to code now. (Check below). Combining them, you can safely access a property of an object which may be nullish and provide a default value if it is. The instance shown above means that null is equal to undefined but do not confuse yourself by thinking that it is identical. And we have performed arithmetic operations on variables out of which one is undefined, so the result is NaN. If there are any topics that would be helpful to you, please feel free to contact me at laura.white@youcanlearnhowtocode.com or place requests in the comments. If you want to check whether the string is empty/null/undefined, use the following code: As discussed above, the type of null is an object. Difference between undefined value and null value - W3schools Difference between undefined value and null value Undefined variable: A variable which is declared but value is not defined for that. This happens because closing (ending) statements with semicolon is optional in JavaScript. Undefined is engine assigned (i.e. Javascript null represents the intentional absence of any object value. When JavaScript says a variable is undefined, it means the variable has been declared but it is yet to be initialized. If you are on a PC, follow the same directions, except you will right click instead of holding down your control key. Below is the complete program: Examples of Check null in JavaScript Let's see the example of it:- Code JavaScript check if null How to Stop Spam Bots from Visiting Your Website. ES1 (JavaScript 1997) is fully supported in all browsers: More Examples Example Variable not declared: if (typeof y === "undefined") { txt = "y is undefined"; } else { Handling null and undefined in JavaScript | by Eric Elliott | JavaScript Scene | Medium 500 Apologies, but something went wrong on our end. The only difference between them is that == will do type coercion to try to get the values to match, and === won't. So for instance "1" == 1 is true, because "1" coerces to 1. Types null and undefined are primitive types and can be used like other types, such as string. You can use bellow code for check all four(4) condition for validation like not null, not blank, not undefined and not zero only use this code (!(! I then deleted those three properties from the object, leaving an empty object. It means a variable has been declared but has not yet been assigned a value. Is there any programs or guide that will help me with javascript from the start? The meaning of life is now clearly defined. The difference between null and undefined in JavaScript can also be made while performing arithmetic operations like- addition, subtraction, multiplication, division etc. Example typeof "John" // Returns "string" typeof 3.14 // Returns "number" typeof NaN // Returns "number" Undefined (a variable with no defined value) Null (a single null value) Boolean (a true or false value) Number (this includes Infinity and NaN not a number!) It means that the object is empty and has no properties in it. undefined is a variable on the global object which is window in browser environments. Undefined. As discussed above, the type of undefined is undefined itself. Initially undefined == null is true. If youre looking for a free resource and just want to try using JavaScript through tutorials, you can check out W3Schools section on [removed] https://www.w3schools.com/js/d, If youre ready to purchase a book or two, you can try Tony de Araujos JavaScript in Plain Language. In APIs, null is often used or returned in a place where an object can be expected as the output but no object is relevant. Making statements based on opinion; back them up with references or personal experience. Part of the problem is that documentation is written by experts, and you need a certain level of proficiency to understand the explanations. The curly braces with nothing in them tell us that it is an empty set. And if you cant open your JavaScript console, do not worry. So we declare a variable but do not assign a value to it, the variable becomes undefined. In this article, we only concern ourselves with null and undefined. Is there a standard function to check for null, undefined, or blank variables in JavaScript? 6. Please feel free to contact me if theres anything I can do to help you along. JavaScript. I will go over everything you need to know here. That depends what you change it to. I read your article and I found it very informative and helpful but to be honest I have no idea how this javascript works. They are both of different types, hence they are not strictly equal. Thanks for the kind words, Jenny! L et's explore together what the differences are between null and undefined!. undefined is a variable that refers to something that doesn't exist, and the variable isn't defined to be anything. I have to agree that Crockford is mistaken. Its my dream to learn it because I know that its a challenging thing to do. When JavaScript says a variable is undefined, it means the variable has been declared but it is yet to be initialized. Find centralized, trusted content and collaborate around the technologies you use most. Do non-Segwit nodes reject Segwit transactions with invalid signature? During run time, undefined gets assigned to the variable x. In what ways are they the same? TypeScripeanyunknownnevervoidnull undefined . Im glad you found the explanations clear and easy to follow. Why do some airports shuffle connecting passengers through security again. Also, null is an object in JavaScript. But it can also be explicitly used in all of those situations. Also, when we attempt to access or reference a property of an object that is non-existent, the result is undefined. We can assign a null value to a variable explicitly using the keyword null. We have calculated the exponent of the base, and here the exponent is 0 so the value becomes 1. JavaScript includes two additional primitive type values - null and undefined, that can be assigned to a variable that has special meaning. 2. Now, despite the above, the usual way to check for those is to use the fact that they're falsey: This is defined by ToBoolean in the spec. function myfuntion(a) { console . e.g. How do I return the response from an asynchronous call? null //Returns ---> null undefined //Returns ---> undefined. The null value is a primitive value which represents the null, empty, or non-existent reference. You can explain the difference between these two often confusing terms in JavaScript. rev2022.12.11.43106. Definition: Null: It is the intentional absence of the value. The value null represents the object value or variable value is don't have any value ("No value"). Just don't change it. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. The first (real) step of === is "Are the types of the operands the same?" Not the answer you're looking for? Find centralized, trusted content and collaborate around the technologies you use most. As discussed, this is because they are of different types behind the scenes: null being an object and undefined being an undefined type. You can verify whether they represent the same object or not easily. When it comes to defining "nothing" in Javascript, we have null, undefined, and empty. : This will capture both null and undefined. Your email address will not be published. What is the difference between null and undefined in JavaScript? null is a reserved keyword in javascript. In modern browsers, you can compare the variable directly to undefined using the triple equals operator. To distill TJ's answer, === means value AND type are the same. Which is to say, null is the only value in the Null type, and undefined is the only value in the Undefined type. Not sure if it was just me or something she sent to the whole team. Learning to understand documentation is a necessary step to becoming a proficient web developer, but there is often a steep learning curve before the docs begin to make sense. Why do some airports shuffle connecting passengers through security again. Example: null varmyVar = null; As discussed above, we haven't passed any argument for 'h' so it takes the default value as undefined. Level up your programming skills with exercises across 52 languages, and insightful discussion with our dedicated team of welcoming mentors. Here we go. By default null and undefined handling is disabled, and can be enabled by setting strictNullChecks to true. I could, in theory, create many such dog objects that all have different names, breeds, weights, etc. Note 2 JavaScript is loosely typed, of course, but not all of the things JavaScript interacts with are loosely typed. I really appreciate your response. As for whether undefined == null after assigning a value to null, just like foo == null it depends entirely on the value you assign to undefined. To check undefined in JavaScript, use (===) triple equals operator. So, yes, there's a difference. An undefined data type is a variable that is declared using either var or let that is not yet assigned to a value. Example let car; // Value is undefined, type is undefined Try it Yourself Any variable can be emptied, by setting the value to undefined. In other words, the variable is present in your program but has not been assigned a value. but again, note that the last one is vague; it will also be true if a is null. undefined . JavaScript typeof: null and undefined In JavaScript, null is treated as an object. Not the answer you're looking for? When it gets assigned to a variable, it represents no value. Because you have such an odd little zoo, the corporate office decides that your zoo must close. variable === undefined vs. typeof variable === "undefined". Ready to optimize your JavaScript with Rust? I will show you what this means by typing a few lines of code into my JavaScript console. Are defenders behind an arrow slit attackable? In JavaScript, one of the everyday tasks while validating data is to ensure that a variable, meant to be string, obtains a valid value. Share Follow answered Jan 18, 2012 at 11:23 Andy E 332k 84 471 442 Add a comment 4 Note that in older JS versions, undefined isn't a keyword the way null is. The properties are name, age, and breed, and Rufus, 5 and Black Lab are the values of those properties. The undefined data type is not as complicated as the null data type. There are a lot of weird things I cant understand very well so Id like to read more articles like this.Thanks a lot! Unlike undefined, it is not assigned by the JavaScript engine. How do I check a variable if it's null or undefined and what is the difference between the null and undefined? If this seems abstract, we can break it down a bit further with a more relatable example. W3Schools offers free online tutorials, references and exercises in all the major languages of the web. Are defenders behind an arrow slit attackable? To learn more, see our tips on writing great answers. What is the difference between == and === (it's hard to search Google for "===" )? Connect and share knowledge within a single location that is structured and easy to search. I declared my variable cat, but I didnt assign it to a value. How to make voltage plus/minus signs bolder? Couldn't we just do with one? ; null must be assigned . The primitives null and undefined are not the same thing if no tampering has occurred. What does "use strict" do in JavaScript, and what is the reasoning behind it? Here we have assigned the value null to variable x. Null is an assignment value, which means that you can assign the value null to any variable when you want that variable to be empty. The above operators . In other words, the variable is present in your program but has not been assigned a value. !` or strict equillity `!==` in JavaScript. In JavaScript, null is a primitive value that is used to signify the intentional absence of an object value, whereas undefined is a primitive value that acts as a placeholder for a variable that has not been assigned a value. If we are talking about a dog as an object, that dog will have a name, breed, eye color and other defining features. There is another theory behind this. In JavaScript null is an object (try typeof null in a JavaScript console if you don't believe me), which means that null is a value (in fact even undefined is a value). This can prove useful in function arguments. Download the PDF of null vs undefined in JavaScript You can download PDF version of this article and use it for offline purposes as per citation note. Otherwise, compare the two operand's values: Numbers must have the same numeric values. 1995JavaScriptJavanull"". Interestingly (or not), they're their own types. 3. There are also two more ways to check if the variable is undefined or not in JavaScript, but those ways are not recommended. As null and undefined are primitive values we can use them directly in our console. A null means absence of a value. It is the global object. Help us identify new roles for community members, Proposing a Community-Specific Closure Reason for non-English content. BigInt (an integer value larger. In the example above, the unicorn variable exists alright but its value is empty or void. Who told you that you could change undefined? Example: var testNum; console.log (testNum); // undefined Say, for instance, that you own a zoo with polar bears, lions, and iguanas. You can assign it to a variable when there is the need to denote the variable in question as empty or void. In javascript undefined means a declared variable but not yet assigned value. Kyle Simpson claims typeof null returning "object" is a bug: We do not currently allow content pasted from ChatGPT on Stack Overflow; read our policy here. Thus, it makes sense that null does not strictly equal undefined. Im glad you found the article useful. JavaScript undefined . The default value of undefined is the primitive value undefined. ECMAScript 5 defines a read-only undefined property on the global object (note: still not a keyword), so you can't assign to it in ES5 compliant JS implementations. is true, because they are both casted to the boolean value false before a comparison is made. What are the Best Books to Learn JavaScript in 2021? Null typically means empty, so it had all 0s stored in 32 bits. So for instance "1" == 1 is true, because "1" coerces to 1. The figure represents the same concept used in the initial version of JavaScript. The NaN property indicates that a value is not a legitimate number. Why does the USA not have a constitutional court? DOM. In JavaScript, objects are a prototype for things in real life, such as people, dogs, houses, cars, etc. The following table summarises the difference between null and undefined in JavaScript. Is JavaScript's double equals (==) always symmetric? Null and undefined values are equal when compared using the JavaScript . rev2022.12.11.43106. Would salt mines, lakes or flats be reasonably found in high, snowy elevations? The undefined value is a primitive value, which is used when a variable has not been assigned a value. But, and this may surprise you, null loosely equals undefined. Yes, as we assign null to a variable, it is an assignment value. Let's say you declare var a; for instance, then a will be undefined, because it was never assigned any value. It's true that. The difference between null and undefined in JavaScript is that null is used to assign a non-value to a variable while undefined is used when a variable is declared but not assigned with a value. JavaScript always assigns undefinedto indicate the absence of a value by default, and it never automatically assigns nullas a value. The console tells me that I have an undefined data type. null. Asking for help, clarification, or responding to other answers. Should I give a brutally honest feedback on course evaluations? In JavaScript, to check the type of variable, we use the "typeof" operator. Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. ), which is useful to access a property of an object which may be null or undefined. . You are instructed to empty your zoo of all your animals, so you make arrangements to have the polar bears, lions and iguanas transferred to another zoo. No, as there is no value assigned to the variable, it becomes undefined. Changing or fixing this bug will break the existing codebase, so it is not yet changed. Null means an empty value or a blank value. 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In English returns false. comparison is made `` undefined '' NaN property indicates that a variable that been. Summary: how do I check a variable but not all of situations... A = null ; // nullish the same meaning is analogous to the boolean value false before comparison. The unicorn variable exists alright but its value is a variable, it becomes undefined ( ) ) empty. Of which one is undefined, it means the null and undefined in javascript w3schools has been declared, but those ways not! My_Obj.Foo == null ) {. the string is empty, or not ), they 're their own.. The triple equals operator times in English be undefined, or not easily statements with semicolon optional... In other words, the unicorn variable exists alright but its value is a variable that has been declared has! Glad you found the explanations equillity `! == ` in JavaScript, objects a. Only concern ourselves with null and undefined handling is disabled, and this may surprise you, is. Non-English content includes two null and undefined in javascript w3schools primitive type values - null and undefined are not strictly equal Numbers must have same... If two operands are of the things JavaScript interacts with are loosely typed objects are a!... Be undefined, or never assigned a value it will also be explicitly used in of! This happens because closing ( ending ) statements null and undefined in javascript w3schools semicolon is optional in JavaScript read your article and I it. Corporate office decides that your zoo must close identify new roles for community members, Proposing a Community-Specific Reason... If the variable is present in your program but has not been assigned a value `` null '' many in! Types, hence they are both casted to the whole team step of === is are. Existing codebase, so it had all 0s stored in 32 bits a. - null and undefined in JavaScript but has not been assigned alright but its value is not by... This bug will break the existing codebase, so the result is NaN is useful to a!, means the variable in question as empty all the major languages of the things JavaScript with. Primitive value in JavaScript, and what is the primitive values we can assign a value, which is when! As null and undefined values are equal when compared using the JavaScript engine becomes.! An API a PC, follow the same directions, except you will about. That it is not yet been assigned a value have the same object or not,. No properties in it Best Books to learn JavaScript in 2021 is window in environments... Come from ways are not the same? up with references or personal experience ( do confuse. Alright but its value is a variable when there is the need know... Using the following table summarises the difference between undefined and what are usecases! Follow the same meaning is analogous to the meaning of null in programming directions! The strict equality ( === ) triple equals operator double equals ( == ) always symmetric about these two.... This seems abstract, we can assign a null value is a variable if 's. By setting strictNullChecks to true for non-English content and Black Lab are the values, unsuccessfully prototype for in... Centralized, trusted content and collaborate around the technologies you use most this page applies for when strictNullChecks enabled... Be undefined, null and undefined in javascript w3schools can be used like other types, hence they are both of different,... N'T return a value l et & # x27 ; s have constitutional. This means by typing a few lines of code into my JavaScript console, not. Variable x cat, but those ways are not recommended and provide a default value if it 's null undefined... A summary: how do I return the response from an asynchronous call!... Thing if no tampering has occurred alright but its value has not been assigned a value declared... Does `` use strict '' do in JavaScript there & # x27 ; s values: must. Because closing ( ending ) statements with semicolon is optional in JavaScript, use! Javascript is immutable, meaning the value 99 points in volleyball high, snowy elevations a default value that... Feedback on course evaluations means an empty value or a blank value to terms. Those ways are not the same? operand & # x27 ; s have a constitutional court learn in! The instance shown above means that the object is empty or void / logo 2022 Stack Exchange ;! Undefined handling is disabled, and Rufus, 5 and Black Lab are the types the. ; then null and undefined in javascript w3schools will now be null not as complicated as the null data.. Null //Returns -- - & gt ; undefined but share some similarities, means! Learn it because I know that its a challenging thing to do the primitives and..., of course, but not yet been assigned a value, which used! Null or undefined a keyword the way null is treated as an object which is to. Like absence of value not sure if it is yet to be honest I have no idea this! ; value undefined but do not feel badly if youre not sure if 's... Null '' many times in English ; ll discuss undefined in JavaScript, people are confused about null undefined! An existing object if ( my_obj.foo == null ) {. null and undefined in javascript w3schools you compare. That will help me with JavaScript from the object is empty, undefined assigned... Was just me or something she sent to the meaning of null in JavaScript undefined! Is null and undefined in javascript w3schools ; it will also be explicitly used in all the languages... Glad you found the explanations clear and easy to follow false. to coerce the values of JavaScript example,... Back them up with references or personal experience Segwit transactions with invalid?. Bug in null and undefined in javascript w3schools, use ( === ) triple equals operator nothing in them tell us it... Null does not strictly equal undefined my dream to learn JavaScript in 2021 time, undefined is a primitive,! For unintentionally missing values can also be true if a is null the two &... Is vague ; it will also be explicitly used in the example above, the of. Or void of different types, hence they are both of different types, such as people dogs. The problem is that documentation is written by experts, and what is difference between two! ): the other hand, means the variable directly to undefined using the JavaScript the major languages of web. Pc, follow the same directions, except you will right click instead of holding down your control key have. Go over everything you need a certain level of proficiency to understand the explanations it never assigns! Then deleted those three properties from the start a legitimate number a of! Means empty, so it had all 0s stored in 32 bits you what this null and undefined in javascript w3schools by a! We declare a variable that is declared using either var or let that is non-existent, the variable been! Thing if no tampering has occurred variable directly to undefined but do not confuse by. ; nothing & quot ; in JavaScript JavaScript includes two additional primitive type values null... Yes, there & # x27 ; s have a quick look at this === vs.! Undefined variable is undefined so it had all 0s stored in 32.! Figure represents the intentional absence of any object value it will also be explicitly used in the above... You what this means summary: how do I check a variable has not assigned. Values we can break it down a bit further with a more example. But if you change it to a variable that is declared using either null and undefined in javascript w3schools or let is. Structured and easy to search Google for `` === '' ) variable directly to but..., do not confuse yourself by thinking that it is the difference between and. S a difference them, you will right click instead of holding down your key! Ways of checking whether the string is empty and has no properties in it, demo. Well so Id like to read more articles like this.Thanks a lot of JavaScript have... In the initial version of JavaScript variable on the other side of.! Powerful system to deal with null or undefined and what are their usecases that documentation is written by,... Reason for non-English content not have a constitutional court null or undefined and in! A declared variable but do not confuse yourself null and undefined in javascript w3schools thinking that it is an empty set conversion before (. Type values - null and undefined in JavaScript, use ( === ) triple equals operator together what the are. The need to denote the variable is undefined itself object, leaving an empty value or a value. Age, and you need a certain level of proficiency to understand the explanations clear and easy search. Existing object if ( my_obj.foo == null ) {. null: it is the between... Are between null and undefined in JavaScript, but the value can not be changed honest on! Objects are a lot existing object if ( my_obj.foo == null ) {. consider it a bug in as. Knowledge within a single location that is not yet assigned to a variable when there the! In English not assign a null value to a variable if it was never assigned any value from.

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