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Raw Queries and Responses

1. Shard Calculation

Query:

Response:

Calculated Shard: 198 (from laksa009)

2. Crawled Status Check

Query:

curl -X POST \
  'http://laksa198.int.ahrefs:8124/' \
  -H 'Content-Type: text/plain' \
  -H 'X-ClickHouse-Database: crawler3' \
  -H 'Authorization: Basic YXBpOg==' \
  -d 'SELECT getAhrefsURLFromUnparsed(src_unparsed) AS found_url, ifNull(toUnixTimestamp(download_stamp), 0) AS crawl_time, ifNull(toUnixTimestamp(props_url_first_seen), 0) AS first_indexed_time, download_http_code AS http_code, src_unparsed AS src_unparsed, src_root_hash AS src_root_hash, history_drop_reason AS history_drop_reason, meta_title AS meta_title, meta_descriptions AS meta_descriptions, attrs_boilerpipe_text AS attrs_boilerpipe_text, attrs_markdown AS attrs_markdown, attrs_readable_markdown AS attrs_readable_markdown, meta_canonical AS meta_canonical FROM crawler3.page_info_local FINAL PREWHERE (src_root_hash, src_unparsed) IN ((getAhrefsRootHashFromUnparsed(getAhrefsUnparsedNoserviceFromURL(\'https://net-informations.com/q/js/exp.htm\')), getAhrefsUnparsedNoserviceFromURL(\'https://net-informations.com/q/js/exp.htm\'))) FORMAT JSONEachRow'

Response:

{"found_url":"https:\/\/net-informations.com\/q\/js\/exp.htm","crawl_time":1774902694,"first_indexed_time":1707523369,"http_code":200,"src_unparsed":"com,net-informations!\/q\/js\/exp.htm s443","src_root_hash":"11421169524120371598","history_drop_reason":null,"meta_title":"Function Declarations vs. Function Expressions in JavaScript","meta_descriptions":["The main difference between function expression and function declaration is that function expressions load only when the interpreter reaches that line of code whereas function declarations load before any code is executed."],"attrs_boilerpipe_text":"The primary distinction between function expressions and function declarations lies in their load time within the code execution process. Function expressions are created and become available only when the interpreter reaches the specific line of code where they are defined. In contrast, function declarations are hoisted to the top of their scope during the initial stages of the code execution, making them accessible and ready for use before any other code is executed. As a result, function expressions are subject to lexical scoping and are not accessible until their definition is reached, while function declarations enjoy the advantage of being available throughout their scope, even before their actual definition in the code.\nFunction Expression\nFunction expressions, like any other expressions in JavaScript, are evaluated when the step-by-step execution of the code reaches the specific line where the function expression is defined. As a result, if you attempt to invoke a function expression before it has been reached and defined in the code, an error will occur.\nThis is because function expressions are not hoisted to the top of their scope during the creation phase like function declarations. Instead, they are created and become available at the exact point in the code where they are defined. Therefore, trying to call a function expression before its definition is encountered during execution will result in a ReferenceError, as the function expression is not yet accessible at that particular moment in the code.\nContinue Reading...\nexample\nfunctionExp();\nvar functionExp = function() {\n  console.log(\"Example:  function expression\");\n};\nOutput:\nHelloWorld.js:2\nfunctionExp();\n^\nTypeError: functionExp is not a function\n    at Object.<anonymous> (HelloWorld.js:2:1)\n    at Module._compile (internal\/modules\/cjs\/loader.js:959:30)\n    at Object.Module._extensions..js (internal\/modules\/cjs\/loader.js:995:10)\n    at Module.load (internal\/modules\/cjs\/loader.js:815:32)\n    at Function.Module._load (internal\/modules\/cjs\/loader.js:727:14)\n    at Function.Module.runMain (internal\/modules\/cjs\/loader.js:1047:10)\n    at internal\/main\/run_main_module.js:17:11\nIf you call a\nfunction declaration\ninstead, it'll always work, because no code can be called until all declarations are loaded.\nTo avoid such errors, it is essential to ensure that function expressions are defined before they are invoked or called in the code, ensuring proper execution and behavior of the JavaScript program.\nFunction Declaration\nA function declaration is indeed a distinct syntactical category in JavaScript and is not considered a statement or expression. It is a fundamental construct used to define a named function within a given scope.\nexample\nfunctionDecl();\nfunction functionDecl() {\n  console.log(\"Example:  function declaration\");\n}\nOutput:\nExample:  function declaration\nWhen the code containing a function declaration is executed, the function is processed during the creation phase of the execution context, before any step-by-step code is executed. This process is known as \"hoisting.\" During hoisting, the function is created, and its definition is made available throughout the entire scope in which the declaration appears.\nA key feature of function declarations is that they are given a proper name (e.g., functionDecl() in the given example), and this name is associated with the function itself in the scope where the declaration is found. This means that you can call the function using its name anywhere in the same scope, even before the function declaration in the code.\nConclusion\nFunction declarations play a fundamental role in JavaScript programming, enabling the creation of named functions that can be accessed and reused throughout the program's scope, promoting modularity and maintainability in code design. Understanding the concept of hoisting and how function declarations work is crucial for writing efficient and organized JavaScript code.","attrs_markdown":"[Home](https:\/\/net-informations.com\/) [AI](https:\/\/net-informations.com\/ai\/default.htm) [Quantum Computing](https:\/\/net-informations.com\/qc\/default.htm) [Data Science](https:\/\/net-informations.com\/ds\/default.htm) [Python](https:\/\/net-informations.com\/python\/default.htm) [Machine Learning](https:\/\/net-informations.com\/ml\/default.htm) [R](https:\/\/net-informations.com\/r\/default.htm) [Java](https:\/\/net-informations.com\/java\/default.htm) [HTML](https:\/\/net-informations.com\/html\/default.htm) [CSS](https:\/\/net-informations.com\/css\/default.htm) [JavaScript](https:\/\/net-informations.com\/js\/default.htm) [C](https:\/\/net-informations.com\/c\/default.htm) [C++](https:\/\/net-informations.com\/cpp\/default.htm) [C\\#](https:\/\/net-informations.com\/csharp\/default.htm) [TypeScript](https:\/\/net-informations.com\/ts\/default.htm) [jQuery](https:\/\/net-informations.com\/jq\/default.htm) [ASP.Net](https:\/\/net-informations.com\/asp\/default.htm) [Assembly](https:\/\/net-informations.com\/asm\/default.htm) [Bash](https:\/\/net-informations.com\/bash\/default.htm) [VB.Net](https:\/\/net-informations.com\/vb\/default.htm) [Cryptography](https:\/\/net-informations.com\/cg\/default.htm) [Colors](https:\/\/net-informations.com\/q\/web\/color-codes.htm) [IT and Web](https:\/\/net-informations.com\/q\/mis\/default.htm) [C\\# Examples](https:\/\/net-informations.com\/q\/faq\/default.htm) [Difference Between](https:\/\/net-informations.com\/q\/diff\/default.htm) [Windows 11](https:\/\/net-informations.com\/q\/w11\/default.htm)\n\n\\>\n\nDigital World\n\n1. [HTML Colors](https:\/\/net-informations.com\/q\/web\/default.htm)\n2. [Windows 11 Guide](https:\/\/net-informations.com\/q\/w11\/default.htm)\n3. [JavaScript Programming](https:\/\/net-informations.com\/q\/js\/default.htm)\n4. [C\\# Programming](https:\/\/net-informations.com\/q\/cs\/default.htm)\n5. [Conversion](https:\/\/net-informations.com\/q\/m\/default.htm)\n6. [Python Programming](https:\/\/net-informations.com\/q\/py\/default.htm)\n7. [Difference](https:\/\/net-informations.com\/q\/diff\/default.htm)\n8. [.Net Frequently Asked Questions (C\\#, Asp.Net and VB.Net)](https:\/\/net-informations.com\/q\/faq\/default.htm)\n9. [What is IT (Information Technology) ?](https:\/\/net-informations.com\/q\/mis\/default.htm)\n\n# var functionName = function() {} vs function functionName() {}\nBy: [Rajesh P.S.](https:\/\/net-informations.com\/rajeshps.htm)\n\nThe primary distinction between function expressions and function declarations lies in their load time within the code execution process. Function expressions are created and become available only when the interpreter reaches the specific line of code where they are defined. In contrast, function declarations are hoisted to the top of their scope during the initial stages of the code execution, making them accessible and ready for use before any other code is executed. As a result, function expressions are subject to lexical scoping and are not accessible until their definition is reached, while function declarations enjoy the advantage of being available throughout their scope, even before their actual definition in the code.\n\n## Function Expression\nFunction expressions, like any other expressions in JavaScript, are evaluated when the step-by-step execution of the code reaches the specific line where the function expression is defined. As a result, if you attempt to invoke a function expression before it has been reached and defined in the code, an error will occur.\n\nThis is because function expressions are not hoisted to the top of their scope during the creation phase like function declarations. Instead, they are created and become available at the exact point in the code where they are defined. Therefore, trying to call a function expression before its definition is encountered during execution will result in a ReferenceError, as the function expression is not yet accessible at that particular moment in the code.\n\n**Continue Reading...**\n\n**example**\n\nfunctionExp(); var functionExp = function() { console.log(\"Example: function expression\"); };\n\n**Output:**\n\nHelloWorld.js:2 functionExp(); ^ TypeError: functionExp is not a function at Object.\\<anonymous\\> (HelloWorld.js:2:1) at Module.\\_compile (internal\/modules\/cjs\/loader.js:959:30) at Object.Module.\\_extensions..js (internal\/modules\/cjs\/loader.js:995:10) at Module.load (internal\/modules\/cjs\/loader.js:815:32) at Function.Module.\\_load (internal\/modules\/cjs\/loader.js:727:14) at Function.Module.runMain (internal\/modules\/cjs\/loader.js:1047:10) at internal\/main\/run\\_main\\_module.js:17:11\n\nIf you call a **function declaration** instead, it'll always work, because no code can be called until all declarations are loaded.\n\n![javascript var functionName = function() {} vs function functionName() {}](https:\/\/net-informations.com\/q\/js\/img\/function-declaration.png)\n\nTo avoid such errors, it is essential to ensure that function expressions are defined before they are invoked or called in the code, ensuring proper execution and behavior of the JavaScript program.\n\n## Function Declaration\nA function declaration is indeed a distinct syntactical category in JavaScript and is not considered a statement or expression. It is a fundamental construct used to define a named function within a given scope.\n\n**example**\n\nfunctionDecl(); function functionDecl() { console.log(\"Example: function declaration\"); }\n\n**Output:**\n\nExample: function declaration\n\nWhen the code containing a function declaration is executed, the function is processed during the creation phase of the execution context, before any step-by-step code is executed. This process is known as \"hoisting.\" During hoisting, the function is created, and its definition is made available throughout the entire scope in which the declaration appears.\n\nA key feature of function declarations is that they are given a proper name (e.g., functionDecl() in the given example), and this name is associated with the function itself in the scope where the declaration is found. This means that you can call the function using its name anywhere in the same scope, even before the function declaration in the code.\n\n### Conclusion\nFunction declarations play a fundamental role in JavaScript programming, enabling the creation of named functions that can be accessed and reused throughout the program's scope, promoting modularity and maintainability in code design. Understanding the concept of hoisting and how function declarations work is crucial for writing efficient and organized JavaScript code.\n\n[Next \\> How to append values to an array in JavaScript?](https:\/\/net-informations.com\/q\/js\/push.htm)\n\n1. [Difference between using \"let\" and \"var\" in JavaScript](https:\/\/net-informations.com\/q\/js\/let.htm)\n2. [How to Use Array forEach() in JavaScript](https:\/\/net-informations.com\/q\/js\/foreach.htm)\n3. [How to Remove Duplicate Values from a JavaScript Array?](https:\/\/net-informations.com\/q\/js\/duplicates.htm)\n4. [How To Get a Timestamp in JavaScript](https:\/\/net-informations.com\/q\/js\/time.htm)\n\n1. [How to append values to an array in JavaScript?](https:\/\/net-informations.com\/q\/js\/push.htm)\n2. [How To Remove a Property from a JavaScript Object](https:\/\/net-informations.com\/q\/js\/prop.htm)\n3. [Which equals operator (== vs ===) should be used in JavaScript comparisons?](https:\/\/net-informations.com\/q\/js\/equal.htm)\n4. [How to Capitalize the First Letter of Each Word in JavaScript](https:\/\/net-informations.com\/q\/js\/cap.htm)\n5. [Get the size of the screen\/browser window \\| JavaScript\/jQuery](https:\/\/net-informations.com\/q\/js\/size.htm)\n6. [Difference between setInterval and setTimeout in JavaScript](https:\/\/net-informations.com\/q\/js\/delay.htm)\n7. [Can't set headers after they are sent to the client](https:\/\/net-informations.com\/q\/js\/header.htm)\n8. 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All other trademarks are property of their respective owners.","attrs_readable_markdown":"The primary distinction between function expressions and function declarations lies in their load time within the code execution process. Function expressions are created and become available only when the interpreter reaches the specific line of code where they are defined. In contrast, function declarations are hoisted to the top of their scope during the initial stages of the code execution, making them accessible and ready for use before any other code is executed. As a result, function expressions are subject to lexical scoping and are not accessible until their definition is reached, while function declarations enjoy the advantage of being available throughout their scope, even before their actual definition in the code.\n\n## Function Expression\nFunction expressions, like any other expressions in JavaScript, are evaluated when the step-by-step execution of the code reaches the specific line where the function expression is defined. As a result, if you attempt to invoke a function expression before it has been reached and defined in the code, an error will occur.\n\nThis is because function expressions are not hoisted to the top of their scope during the creation phase like function declarations. Instead, they are created and become available at the exact point in the code where they are defined. Therefore, trying to call a function expression before its definition is encountered during execution will result in a ReferenceError, as the function expression is not yet accessible at that particular moment in the code.\n\n**Continue Reading...**\n\n**example**\n\nfunctionExp(); var functionExp = function() { console.log(\"Example: function expression\"); };\n\n**Output:**\n\nHelloWorld.js:2 functionExp(); ^ TypeError: functionExp is not a function at Object.\\<anonymous\\> (HelloWorld.js:2:1) at Module.\\_compile (internal\/modules\/cjs\/loader.js:959:30) at Object.Module.\\_extensions..js (internal\/modules\/cjs\/loader.js:995:10) at Module.load (internal\/modules\/cjs\/loader.js:815:32) at Function.Module.\\_load (internal\/modules\/cjs\/loader.js:727:14) at Function.Module.runMain (internal\/modules\/cjs\/loader.js:1047:10) at internal\/main\/run\\_main\\_module.js:17:11\n\nIf you call a **function declaration** instead, it'll always work, because no code can be called until all declarations are loaded.\n\n![javascript var functionName = function() {} vs function functionName() {}](https:\/\/net-informations.com\/q\/js\/img\/function-declaration.png)\n\nTo avoid such errors, it is essential to ensure that function expressions are defined before they are invoked or called in the code, ensuring proper execution and behavior of the JavaScript program.\n\n## Function Declaration\nA function declaration is indeed a distinct syntactical category in JavaScript and is not considered a statement or expression. It is a fundamental construct used to define a named function within a given scope.\n\n**example**\n\nfunctionDecl(); function functionDecl() { console.log(\"Example: function declaration\"); }\n\n**Output:**\n\nExample: function declaration\n\nWhen the code containing a function declaration is executed, the function is processed during the creation phase of the execution context, before any step-by-step code is executed. This process is known as \"hoisting.\" During hoisting, the function is created, and its definition is made available throughout the entire scope in which the declaration appears.\n\nA key feature of function declarations is that they are given a proper name (e.g., functionDecl() in the given example), and this name is associated with the function itself in the scope where the declaration is found. This means that you can call the function using its name anywhere in the same scope, even before the function declaration in the code.\n\n### Conclusion\nFunction declarations play a fundamental role in JavaScript programming, enabling the creation of named functions that can be accessed and reused throughout the program's scope, promoting modularity and maintainability in code design. Understanding the concept of hoisting and how function declarations work is crucial for writing efficient and organized JavaScript code.","meta_canonical":null}

3. Robots.txt Check

Query:

Response:

4. Spam/Ban Check

Query:

Response:

5. Seen Status Check

ℹ️ Skipped - page is already crawled

📄

INDEXABLE

✅

CRAWLED

11 days ago

🤖

ROBOTS ALLOWED

Page Info Filters

Filter	Status	Condition	Details
HTTP status	PASS	`download_http_code = 200`	HTTP 200
Age cutoff	PASS	`download_stamp > now() - 6 MONTH`	0.4 months ago
History drop	PASS	`isNull(history_drop_reason)`	No drop reason
Spam/ban	PASS	`fh_dont_index != 1 AND ml_spam_score = 0`	ml_spam_score=0
Canonical	PASS	`meta_canonical IS NULL OR = '' OR = src_unparsed`	Not set

Page Details

Property	Value
URL	https://net-informations.com/q/js/exp.htm
Last Crawled	2026-03-30 20:31:34 (11 days ago)
First Indexed	2024-02-10 00:02:49 (2 years ago)
HTTP Status Code	200
Meta Title	Function Declarations vs. Function Expressions in JavaScript
Meta Description	The main difference between function expression and function declaration is that function expressions load only when the interpreter reaches that line of code whereas function declarations load before any code is executed.
Meta Canonical	null
Boilerpipe Text	The primary distinction between function expressions and function declarations lies in their load time within the code execution process. Function expressions are created and become available only when the interpreter reaches the specific line of code where they are defined. In contrast, function declarations are hoisted to the top of their scope during the initial stages of the code execution, making them accessible and ready for use before any other code is executed. As a result, function expressions are subject to lexical scoping and are not accessible until their definition is reached, while function declarations enjoy the advantage of being available throughout their scope, even before their actual definition in the code. Function Expression Function expressions, like any other expressions in JavaScript, are evaluated when the step-by-step execution of the code reaches the specific line where the function expression is defined. As a result, if you attempt to invoke a function expression before it has been reached and defined in the code, an error will occur. This is because function expressions are not hoisted to the top of their scope during the creation phase like function declarations. Instead, they are created and become available at the exact point in the code where they are defined. Therefore, trying to call a function expression before its definition is encountered during execution will result in a ReferenceError, as the function expression is not yet accessible at that particular moment in the code. Continue Reading... example functionExp(); var functionExp = function() { console.log("Example: function expression"); }; Output: HelloWorld.js:2 functionExp(); ^ TypeError: functionExp is not a function at Object.<anonymous> (HelloWorld.js:2:1) at Module._compile (internal/modules/cjs/loader.js:959:30) at Object.Module._extensions..js (internal/modules/cjs/loader.js:995:10) at Module.load (internal/modules/cjs/loader.js:815:32) at Function.Module._load (internal/modules/cjs/loader.js:727:14) at Function.Module.runMain (internal/modules/cjs/loader.js:1047:10) at internal/main/run_main_module.js:17:11 If you call a function declaration instead, it'll always work, because no code can be called until all declarations are loaded. To avoid such errors, it is essential to ensure that function expressions are defined before they are invoked or called in the code, ensuring proper execution and behavior of the JavaScript program. Function Declaration A function declaration is indeed a distinct syntactical category in JavaScript and is not considered a statement or expression. It is a fundamental construct used to define a named function within a given scope. example functionDecl(); function functionDecl() { console.log("Example: function declaration"); } Output: Example: function declaration When the code containing a function declaration is executed, the function is processed during the creation phase of the execution context, before any step-by-step code is executed. This process is known as "hoisting." During hoisting, the function is created, and its definition is made available throughout the entire scope in which the declaration appears. A key feature of function declarations is that they are given a proper name (e.g., functionDecl() in the given example), and this name is associated with the function itself in the scope where the declaration is found. This means that you can call the function using its name anywhere in the same scope, even before the function declaration in the code. Conclusion Function declarations play a fundamental role in JavaScript programming, enabling the creation of named functions that can be accessed and reused throughout the program's scope, promoting modularity and maintainability in code design. Understanding the concept of hoisting and how function declarations work is crucial for writing efficient and organized JavaScript code.
Markdown	[Home](https://net-informations.com/) [AI](https://net-informations.com/ai/default.htm) [Quantum Computing](https://net-informations.com/qc/default.htm) [Data Science](https://net-informations.com/ds/default.htm) [Python](https://net-informations.com/python/default.htm) [Machine Learning](https://net-informations.com/ml/default.htm) [R](https://net-informations.com/r/default.htm) [Java](https://net-informations.com/java/default.htm) [HTML](https://net-informations.com/html/default.htm) [CSS](https://net-informations.com/css/default.htm) [JavaScript](https://net-informations.com/js/default.htm) [C](https://net-informations.com/c/default.htm) [C++](https://net-informations.com/cpp/default.htm) [C\#](https://net-informations.com/csharp/default.htm) [TypeScript](https://net-informations.com/ts/default.htm) [jQuery](https://net-informations.com/jq/default.htm) [ASP.Net](https://net-informations.com/asp/default.htm) [Assembly](https://net-informations.com/asm/default.htm) [Bash](https://net-informations.com/bash/default.htm) [VB.Net](https://net-informations.com/vb/default.htm) [Cryptography](https://net-informations.com/cg/default.htm) [Colors](https://net-informations.com/q/web/color-codes.htm) [IT and Web](https://net-informations.com/q/mis/default.htm) [C\# Examples](https://net-informations.com/q/faq/default.htm) [Difference Between](https://net-informations.com/q/diff/default.htm) [Windows 11](https://net-informations.com/q/w11/default.htm) \> Digital World 1. [HTML Colors](https://net-informations.com/q/web/default.htm) 2. [Windows 11 Guide](https://net-informations.com/q/w11/default.htm) 3. [JavaScript Programming](https://net-informations.com/q/js/default.htm) 4. [C\# Programming](https://net-informations.com/q/cs/default.htm) 5. [Conversion](https://net-informations.com/q/m/default.htm) 6. [Python Programming](https://net-informations.com/q/py/default.htm) 7. [Difference](https://net-informations.com/q/diff/default.htm) 8. [.Net Frequently Asked Questions (C\#, Asp.Net and VB.Net)](https://net-informations.com/q/faq/default.htm) 9. [What is IT (Information Technology) ?](https://net-informations.com/q/mis/default.htm) # var functionName = function() {} vs function functionName() {} By: [Rajesh P.S.](https://net-informations.com/rajeshps.htm) The primary distinction between function expressions and function declarations lies in their load time within the code execution process. Function expressions are created and become available only when the interpreter reaches the specific line of code where they are defined. In contrast, function declarations are hoisted to the top of their scope during the initial stages of the code execution, making them accessible and ready for use before any other code is executed. As a result, function expressions are subject to lexical scoping and are not accessible until their definition is reached, while function declarations enjoy the advantage of being available throughout their scope, even before their actual definition in the code. ## Function Expression Function expressions, like any other expressions in JavaScript, are evaluated when the step-by-step execution of the code reaches the specific line where the function expression is defined. As a result, if you attempt to invoke a function expression before it has been reached and defined in the code, an error will occur. This is because function expressions are not hoisted to the top of their scope during the creation phase like function declarations. Instead, they are created and become available at the exact point in the code where they are defined. Therefore, trying to call a function expression before its definition is encountered during execution will result in a ReferenceError, as the function expression is not yet accessible at that particular moment in the code. Continue Reading... example functionExp(); var functionExp = function() { console.log("Example: function expression"); }; Output: HelloWorld.js:2 functionExp(); ^ TypeError: functionExp is not a function at Object.\<anonymous\> (HelloWorld.js:2:1) at Module.\_compile (internal/modules/cjs/loader.js:959:30) at Object.Module.\_extensions..js (internal/modules/cjs/loader.js:995:10) at Module.load (internal/modules/cjs/loader.js:815:32) at Function.Module.\_load (internal/modules/cjs/loader.js:727:14) at Function.Module.runMain (internal/modules/cjs/loader.js:1047:10) at internal/main/run\_main\_module.js:17:11 If you call a function declaration instead, it'll always work, because no code can be called until all declarations are loaded. ![javascript var functionName = function() {} vs function functionName() {}](https://net-informations.com/q/js/img/function-declaration.png) To avoid such errors, it is essential to ensure that function expressions are defined before they are invoked or called in the code, ensuring proper execution and behavior of the JavaScript program. ## Function Declaration A function declaration is indeed a distinct syntactical category in JavaScript and is not considered a statement or expression. It is a fundamental construct used to define a named function within a given scope. example functionDecl(); function functionDecl() { console.log("Example: function declaration"); } Output: Example: function declaration When the code containing a function declaration is executed, the function is processed during the creation phase of the execution context, before any step-by-step code is executed. This process is known as "hoisting." During hoisting, the function is created, and its definition is made available throughout the entire scope in which the declaration appears. A key feature of function declarations is that they are given a proper name (e.g., functionDecl() in the given example), and this name is associated with the function itself in the scope where the declaration is found. This means that you can call the function using its name anywhere in the same scope, even before the function declaration in the code. ### Conclusion Function declarations play a fundamental role in JavaScript programming, enabling the creation of named functions that can be accessed and reused throughout the program's scope, promoting modularity and maintainability in code design. Understanding the concept of hoisting and how function declarations work is crucial for writing efficient and organized JavaScript code. [Next \> How to append values to an array in JavaScript?](https://net-informations.com/q/js/push.htm) 1. [Difference between using "let" and "var" in JavaScript](https://net-informations.com/q/js/let.htm) 2. [How to Use Array forEach() in JavaScript](https://net-informations.com/q/js/foreach.htm) 3. [How to Remove Duplicate Values from a JavaScript Array?](https://net-informations.com/q/js/duplicates.htm) 4. 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Readable Markdown	The primary distinction between function expressions and function declarations lies in their load time within the code execution process. Function expressions are created and become available only when the interpreter reaches the specific line of code where they are defined. In contrast, function declarations are hoisted to the top of their scope during the initial stages of the code execution, making them accessible and ready for use before any other code is executed. As a result, function expressions are subject to lexical scoping and are not accessible until their definition is reached, while function declarations enjoy the advantage of being available throughout their scope, even before their actual definition in the code. ## Function Expression Function expressions, like any other expressions in JavaScript, are evaluated when the step-by-step execution of the code reaches the specific line where the function expression is defined. As a result, if you attempt to invoke a function expression before it has been reached and defined in the code, an error will occur. This is because function expressions are not hoisted to the top of their scope during the creation phase like function declarations. Instead, they are created and become available at the exact point in the code where they are defined. Therefore, trying to call a function expression before its definition is encountered during execution will result in a ReferenceError, as the function expression is not yet accessible at that particular moment in the code. Continue Reading... example functionExp(); var functionExp = function() { console.log("Example: function expression"); }; Output: HelloWorld.js:2 functionExp(); ^ TypeError: functionExp is not a function at Object.\<anonymous\> (HelloWorld.js:2:1) at Module.\_compile (internal/modules/cjs/loader.js:959:30) at Object.Module.\_extensions..js (internal/modules/cjs/loader.js:995:10) at Module.load (internal/modules/cjs/loader.js:815:32) at Function.Module.\_load (internal/modules/cjs/loader.js:727:14) at Function.Module.runMain (internal/modules/cjs/loader.js:1047:10) at internal/main/run\_main\_module.js:17:11 If you call a function declaration instead, it'll always work, because no code can be called until all declarations are loaded. ![javascript var functionName = function() {} vs function functionName() {}](https://net-informations.com/q/js/img/function-declaration.png) To avoid such errors, it is essential to ensure that function expressions are defined before they are invoked or called in the code, ensuring proper execution and behavior of the JavaScript program. ## Function Declaration A function declaration is indeed a distinct syntactical category in JavaScript and is not considered a statement or expression. It is a fundamental construct used to define a named function within a given scope. example functionDecl(); function functionDecl() { console.log("Example: function declaration"); } Output: Example: function declaration When the code containing a function declaration is executed, the function is processed during the creation phase of the execution context, before any step-by-step code is executed. This process is known as "hoisting." During hoisting, the function is created, and its definition is made available throughout the entire scope in which the declaration appears. A key feature of function declarations is that they are given a proper name (e.g., functionDecl() in the given example), and this name is associated with the function itself in the scope where the declaration is found. This means that you can call the function using its name anywhere in the same scope, even before the function declaration in the code. ### Conclusion Function declarations play a fundamental role in JavaScript programming, enabling the creation of named functions that can be accessed and reused throughout the program's scope, promoting modularity and maintainability in code design. Understanding the concept of hoisting and how function declarations work is crucial for writing efficient and organized JavaScript code.
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