The value NaN (Not-a-Number) is a special numeric value that results from an operation that cannot produce a meaningful number.

In option B, parseInt('two') attempts to parse a string that does not begin with a numeral. The function cannot convert 'two' into an integer and therefore correctly returns NaN.

In option C, the division operator (/) triggers numeric type coercion on the string 'five'. Since 'five' cannot be converted into a valid number, it is coerced to NaN. Any arithmetic operation involving NaN as an operand results in NaN.

A. Number('5') successfully converts the string to the number 5. The expression 10 / 5 evaluates to 2, which is a valid number.

D. In JavaScript, division of a non-zero number by 0 does not result in NaN. Instead, it evaluates to Infinity.

1. ECMAScript® 2023 Language Specification (ECMA-262

14th edition):

For parseInt (Option B): Section 19.2.5

parseInt ( string

radix )

describes the parsing process. If the input string does not contain any mathematical integer value

the result is NaN.

For Division and Type Coercion (Option C): Section 13.7

Multiplicative Operators

specifies that for the division A / B

both operands are first converted to numbers using the ToNumeric abstract operation. The string 'five' converts to NaN

and as per Table 22

Number / NaN results in NaN.

For Division by Zero (Option D): Section 6.1.6.1.5

Number::divide ( x

y )

states that if x is finite and non-zero and y is +0

the result is +Infinity.

2. MDN Web Docs (Official Mozilla Documentation for JavaScript):

parseInt(): "If the first character cannot be converted to a number

parseInt() returns NaN." (Source: MDN Web Docs

parseInt()

"Return value" section).

NaN: "NaN is a property of the global object. It is a value representing Not-A-Number. ... It is the returned value when Math functions fail (e.g.

Math.sqrt(-1)) or when a function trying to parse a number fails (e.g.

parseInt('blabla'))." (Source: MDN Web Docs

NaN

"Description" section).

Arithmetic Operators: "If one of the operands is a string that cannot be converted to a number

the result is NaN." (Source: MDN Web Docs

"Arithmetic operators"

"Division (/)" section).

The console.assert() method is the correct choice as it is specifically designed to log an error message to the console if and only if its first argument (the assertion) evaluates to false. This directly fulfills the second requirement. Furthermore, the console object is a standard, globally available feature in both browser JavaScript environments and Node.js, satisfying the third requirement for cross-platform compatibility.

While the first requirement ("Does require an import") appears to be a flawed premise in the question—as no single option satisfies all three conditions—console.assert() is the only choice that correctly implements the core functional logic described in requirements two and three.

A. assert (number % 2 === 0); is incorrect because the assert module is specific to Node.js and is not natively available in browsers, thus failing the cross-platform requirement.

B. console.error(number % 2 === 0); is incorrect because it does not log an error conditionally. It logs the boolean result (true or false) of the expression on every iteration of the loop.

C. console.debug(number % 2 === 0); is incorrect because it logs a debug-level message, not an error, and it does so on every iteration rather than conditionally when the statement is false.

1. Node.js Official Documentation

Console API: The documentation confirms that console.assert(value[

...message]) is part of the global console object and functions as an assertion. It states

"If value is falsy

it writes a message to the console." This confirms its behavior and availability in Node.js without an import. (See: Node.js v18.17.1 Documentation

Console API

console.assert()).

2. MDN Web Docs

Console API: The MDN documentation for the console.assert() method specifies its cross-platform availability and function: "Logs a message and stack trace to the console if the first argument is false." This confirms its behavior and availability in standard web browsers. (See: MDN Web Docs

Web APIs

console.assert()).

The goal is to set the deliveryDate object to 9 days from the current date. The Date.prototype.setDate() method is designed for this. It sets the day of the month for a Date object. Crucially, if the provided day value exceeds the number of days in the current month, the method automatically adjusts the month and year accordingly. The expression (new Date()).getDate() + 9 retrieves the current day of the month (e.g., 15) and adds 9 to it. Passing this result to deliveryDate.setDate() correctly calculates and sets the date to 9 days in the future, handling month and year rollovers.

B. Date.current() is not a standard JavaScript function. The correct static method is Date.now(), which returns milliseconds, an invalid value for the setDate() method.

C. A JavaScript Date object does not have a public property named .date for assignment. Also, new Date(+9) creates a date 9 milliseconds after the 1970 epoch.

D. This option has two errors: it attempts to assign to the non-existent .date property and calls the non-existent Date.current() function.

1. Mozilla Developer Network (MDN) Web Docs

Date.prototype.setDate(): "The setDate() method of a Date instance changes the day of the month for this date according to local time... If the dayValue is outside of the range of date values for the month

setDate() will update the Date object accordingly." This confirms the rollover behavior essential for the correct answer.

Source: Mozilla

Date.prototype.setDate()

Accessed on [Current Date]

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/GlobalObjects/Date/setDate

2. Mozilla Developer Network (MDN) Web Docs

Date.prototype.getDate(): "The getDate() method of a Date instance returns the day of the month for this date according to local time." This confirms the method used to retrieve the current day number.

Source: Mozilla

Date.prototype.getDate()

Accessed on [Current Date]

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/GlobalObjects/Date/getDate

3. ECMAScript® 2023 Language Specification (ECMA-262

14th edition): The behavior of setDate is formally defined. The specification details the internal SetDate abstract operation

which correctly calculates the final date when the day argument causes the month or year to change.

Source: ECMA International

ECMAScript Language Specification

14th Edition

June 2023

Section 21.4.4.25 Date.prototype.setDate ( date ).

To create a secure web server in Node.js without third-party libraries, the built-in https module must be used. This module provides the functionality for creating an HTTPS server, which is essentially an HTTP server operating over a TLS/SSL encrypted connection. The https.createServer() method is the standard way to instantiate such a server, requiring SSL certificate and key files. This directly fulfills the requirement for a "secure web server" using the native Node.js API.

B. const server =require(‘secure-server’);

secure-server is not a core Node.js module. Requiring it would necessitate installing a third-party library, which is explicitly forbidden by the question.

C. const tls = require(‘tls’);

The tls module provides the underlying security protocol (TLS/SSL) but is not the high-level API for creating a secure web (HTTP) server.

D. const http =require(‘http’);

The http module is used to create an unencrypted, insecure web server. This directly contradicts the requirement for a "secure" server.

1. Node.js v18.18.0 Documentation

HTTPS Module: "The https module provides an implementation of the TLS/SSL protocol for Node.js. The API of https is very similar to that of http." The documentation further provides a direct example: const https = require('node:https'); ... https.createServer(options

(req

res) => { ... });

Source: Official Node.js Documentation

https module API. Section: https.createServer(options[

requestListener]).

2. Node.js v18.18.0 Documentation

HTTP Module: "To use the HTTP server and client

one must require('node:http')." This module is explicitly for the unencrypted HTTP protocol.

Source: Official Node.js Documentation

http module API.

3. Node.js v18.18.0 Documentation

TLS (Transport Layer Security) Module: "The node:tls module provides an implementation of the Transport Layer Security (TLS) and Secure Socket Layer (SSL) protocols... It provides a stream-based API for secure communication." This shows it is a lower-level protocol implementation

not the specific API for an HTTPS server.

Source: Official Node.js Documentation

tls module API.

The question requires importing all functions from a module into a single object and then calling them. This is achieved using the ES6 module "namespace import" syntax: import as from ''. This statement imports all named exports from the specified module and assigns them as properties to a newly created object, here named lib. The functions foo and bar can then be correctly called as methods on this lib object.

Note: The provided option 'A' contains a common typographical error where ad is used instead of the correct keyword as. Despite this typo, it is the only option that correctly represents the required namespace import pattern and subsequent function calls.

B: This attempts a "named import," which only imports the specified functions (foo, bar), not every function as required. The syntax is also incorrect, using parentheses () instead of curly braces {}.

C: The syntax import all from ... is not a valid ES6 module syntax for a namespace import. Additionally, it attempts to call functions on universalContainersLib, which was not the alias used in the import.

D: The syntax import from ... is incomplete and invalid. A namespace import requires an alias for the module object, specified with as .

1. Salesforce Lightning Web Components Developer Guide: The documentation explicitly shows the use of standard ES6 modules

including namespace imports. Under "Import from Another Component's JavaScript File

" the guide details the import syntax. The pattern import as ... is consistent with standard JavaScript. (See section: JavaScript Modules).

2. MDN Web Docs - import statement: This is the de-facto standard reference for JavaScript syntax. It defines the namespace import syntax as: import as name from "module-name";. This creates a module namespace object (name) containing all the exports from "module-name". (See section: Syntax > Import a module's contents).

The JavaScript engine will throw a ReferenceError. The function is defined as myfunction (all lowercase), but the invocation is myFunction() (with a capital 'F'). JavaScript is a case-sensitive language, meaning myfunction and myFunction are treated as two distinct identifiers. Since no function named myFunction has been defined in the scope, the attempt to call it results in a ReferenceError. The code inside the myfunction block, including the "use strict"; directive, is never executed.

1. Mozilla Developer Network (MDN) Web Docs: In the "JavaScript Guide > Grammar and types" section

it is explicitly stated: "JavaScript is a case-sensitive language. This means that language keywords

variables

function names

and other identifiers must always be typed with a consistent capitalization of letters." (See "Case sensitivity" subsection).

2. ECMA-262

13th Edition (ECMAScript® 2022 Language Specification): Section 6.1.2

"The Undefined Type

" and Section 7.2.2

"IsUnresolvableReference ( V )

" detail the process of reference resolution. An identifier that cannot be resolved in the current lexical environment

such as the call to the non-existent myFunction

results in an unresolvable reference

which leads to a ReferenceError being thrown.

3. Flanagan

D. (2020). JavaScript: The Definitive Guide (7th ed.). O'Reilly Media. Chapter 2

"Lexical Structure

" Section "Case-Sensitivity

" states

"JavaScript is a case-sensitive language. This means that keywords

variables

function names

and other identifiers must always be typed with a consistent capitalization of letters." (p. 16).

4. Haverbeke

M. (2018). Eloquent JavaScript (3rd ed.). No Starch Press. Chapter 2

"Program Structure

" under the section "Bindings

" explains that bindings (variables and functions) have names

and these names are case-sensitive. The text notes

"The names of bindings

also called identifiers

can be any word... Casing matters—catch and Catch are different names." (p. 23).

Both slice(start, end) and substring(start, end) methods extract a portion of a string. The start parameter specifies the zero-based index at which to begin extraction, and the end parameter specifies the index before which to end extraction. For the string 'Salesforce', the substring 'Sales' begins at index 0 and ends at index 4. Therefore, specifying a start of 0 and an end of 5 will extract characters from index 0 up to, but not including, index 5, resulting in 'Sales'.

1. ECMA International. (2023). ECMAScript® 2023 Language Specification (14th ed.

ECMA-262). Section 22.1.3.26

String.prototype.slice(start

end)

and Section 22.1.3.30

String.prototype.substring(start

end). The specification details that both methods extract characters from the start index up to the end index

where the character at the end index is not included.

2. Massachusetts Institute of Technology. (2013). 6.170 Software Studio

Lecture 2: JavaScript. MIT OpenCourseWare. The lecture notes cover core JavaScript features

including string manipulation methods like slice and substring

explaining their usage for extracting parts of a string based on indices. (ocw.mit.edu)

3. Haverbeke

M. (2018). Eloquent JavaScript (3rd ed.). No Starch Press. Chapter 4

"Data Structures: Objects and Arrays

" section on "Strings and their properties." This text

often used in university curricula

explains that slice and substring are similar in taking start and end indices to create a new string.

The debugger statement programmatically creates a breakpoint in the code. To "step into each function execution," the developer must pause the code before the first function is called. Placing the debugger statement on line 03 accomplishes this. When the code pauses, the developer can use the debugging tools' "Step into" command to enter the findSubTotal function. Upon returning from it, execution will pause at the next line, allowing the developer to then step into addTax, and subsequently addTip. This is the only option that facilitates stepping into all three functions sequentially from a single breakpoint.

A. Using the debugger command on line 05 is too late. It only allows stepping into the addTip function, as findSubTotal and addTax have already executed.

C. The console.trace() method outputs the function call stack to the console but does not pause execution, which is required for stepping into functions.

D. Wrapping a function in console.log() only prints its return value. It does not pause execution or provide a mechanism to step into the function's code.

1. Mozilla Developer Network (MDN) Web Docs: The debugger statement is an official part of the ECMAScript specification. The MDN documentation states

"The debugger statement invokes any available debugging functionality... If no debugging functionality is available

this statement has no effect. The purpose of the debugger statement is to stop the execution of code at a specific point." This supports using debugger to create a breakpoint from which one can step into subsequent code.

Source: MDN Web Docs

debugger statement. Section: "Syntax".

2. Salesforce Lightning Web Components Developer Guide: In the context of JavaScript development for Salesforce (relevant to CRT-600)

the official documentation recommends using browser developer tools and the debugger statement for debugging. It explains how breakpoints pause execution

allowing for inspection and stepping through code.

Source: Salesforce Developers

Lightning Web Components Dev Guide

"Debug Your Code". Section: "Debug JavaScript".

3. Google Chrome for Developers Documentation: This is an authoritative source on using debugging tools. It describes the "Step into next function call" action

which is only available when execution is paused at a breakpoint

such as one created by a debugger statement.

Source: Chrome for Developers

JavaScript debugging reference. Section: "Step through code".

In JavaScript, arrays are reference types. A direct assignment (let arr2 = arr1;) creates a new variable arr2 that points to the same memory location as arr1, not a new array. To create a true copy, a method that returns a new array instance must be used.

The slice() method extracts a portion of an array and returns a new, shallow-copied array object. Similarly, Array.from() creates a new, shallow-copied Array instance from an iterable object like an array. Both methods result in arr2 being a distinct array in memory, independent of arr1.

C. Let arr2 = arr1;

This line creates a reference. The variable arr2 will point to the exact same array object as arr1, not a new one.

D. Let arr2 = arr1.sort();

The sort() method modifies the array in-place and returns a reference to that same, now-sorted, original array.

1. Mozilla Developer Network (MDN) Web Docs

Array.prototype.slice(): "The slice() method returns a shallow copy of a portion of an array into a new array object selected from start to end (end not included) where start and end represent the index of items in that array. The original array will not be modified." (Section: "Return value").

2. Mozilla Developer Network (MDN) Web Docs

Array.from(): "The Array.from() static method creates a new

shallow-copied Array instance from an iterable or array-like object." (Section: "Description").

3. Mozilla Developer Network (MDN) Web Docs

Array.prototype.sort(): "The sort() method sorts the elements of an array in place and returns the reference to the same array

now sorted. The default sort order is ascending..." (Section: "Return value").

4. Eloquent JavaScript

3rd Edition by Marijn Haverbeke (a resource used in many university curricula): "Objects and arrays

on the other hand

are stored differently... When you copy a variable that holds an object

you are copying the reference to that object

not the object itself... If you want to create a new array with the same elements

you can use the slice method with no arguments." (Chapter 4: Data Structures: Objects and Arrays

Section: "Objects and arrays are mutable").

The scenario describes a classic web development issue where a tester sees an outdated version of a webpage due to browser caching, while the developer, who often has caching disabled in their development environment, sees the live version. The most direct actions to resolve this and ensure the tester sees the updated content ("accurate results") are for the tester to bypass their local cache. Both clearing the browser cache (a one-time fix) and disabling the browser cache (a persistent fix for the testing session) will force the browser to download the latest files from the server, thus showing the intended changes.

A. The developer should inspect their browser refresh settings.

This is a diagnostic step to understand why it works for the developer, but it does not directly help the tester see the accurate results on their own machine.

C. The developer should rework the code.

This is premature. There is no evidence of a code defect, as the functionality works in the developer's environment, strongly indicating an environmental issue like caching.

1. Salesforce Lightning Web Components Developer Guide: In the "Develop Your Component" section

under "Preview Your Component

" the documentation frequently advises developers on how to see their most recent changes. A common instruction is: "To ensure that you’re seeing your most recent changes during development

empty the cache and do a hard reload of the page in your browser." This directly supports the actions of clearing or disabling the cache (Options D and B) as a standard procedure to resolve stale content issues.

2. MDN Web Docs (Mozilla Developer Network): As a foundational resource for web technologies used in Salesforce development

MDN's documentation on "HTTP Caching" explains this exact problem. In the "Stale responses" section

it details how browsers store copies of resources. The prescribed user-side solutions are to force a reload that bypasses the cache

which is achieved by clearing the cache or using developer tools to disable it. This principle is fundamental to web development and testing curricula at an academic level. (Reference: MDN Web Docs

HTTP Caching

section on "Forcing a reload").