Salesforce JavaScript Developer I Cert Practice Exam Questions With 100% Correct Answers

Salesforce JavaScript Developer I Cert Practice Exam Questions With 100% Correct Answers Which two syntax examples correctly initialize a value to the variable strLang? A. let strLang = 'javascript'; B. const strLang = 'java' + 'script'; C. let strLang = javascript; D. str strLang = 'javascript'; - answerANSWER: A. let strLang = 'javascript'; B. const strLang = 'java' + 'script'; Additional Info: Note that C doesn't have a value that has single quotes around the word 'javascript' and for D, 'str' is not a proper identifier Which statement sorts the following number array so it is in ascending order? const arr = [7, 3, 400, 10]; A. (); B. ((a, b) => a - b); C. ((a, b) => a < b); D. ((a, b) => b - a); - answerANSWER: B. ((a, b) => a - b); Additional Info: A. The sort() function sorts values as strings, which will sort this as [10, 3, 400, 7]. C. The compare function expects a positive, negative, or 0 to be returned. D. The compare function will actually reverse the order of the numbers. Which statement sorts the following string array so it is in descending order? const arr = ["Banana", "Orange", "Apple", "Mango"]; A. (); B. ((a, b) => a - b); C. se(); D. ((a, b) => b - a); - answerANSWER: C. se(); Additional Info: A. The sort() function sorts values as strings in ASCENDING order: ["Apple", "Banana", "Mango", "Orange"]; B,D. Expect a number array. What are the different data types used in JavaScript? - answerANSWER: There are 8 basic data types in JavaScript: 1. Number for numbers of any kind: integer or floating-point, integers are limited by ±((2^53)-1). 2. BigInt is for integer numbers of arbitrary length. 3. String for strings. A string may have zero or more characters, there's no separate single- character type. 4. Boolean for true/false. 5. NULL for unknown values - a standalone type that has a single value null. Note, typeof null returns "object" even though it is NOT and object. 6. Undefined for unassigned values - a standalone type that has a single value undefined. 7. Object for more complex data structures. 8. Symbol for unique identifiers. Which collections of data are ordered by a key? - answerANSWER: Map and set objects. What is the proper syntax for adding placeholders in template literals? - answerANSWER: Use a dollar sign followed by curly brackets: ${expression}. Additional Info: let name = "John"; // embed a variable alert( `Hello, ${name}!` ); // Hello, John! // embed an expression alert( `the result is ${1 + 2}` ); // the result is 3 Note this only works if you use backticks, `, and not single(') or double(") quotes otherwise the results will be shown as literal, ie: Hello, ${name}! How do you instantiate a value as a BigInt? A. Nothing, JavaScript will automatically cast a number to a BigInt if the value is greater than ((2^53) - 1) B. const bigInt = BigI(); C. const bigInt = n; D. const bigInt = BigI(''); - answerANSWER: C. const bigInt = n; Additional Info: BigInt does NOT work in IE. Given the following Animal constructor: function Animal(size, age) { = size; = age; Talk = false; } Which method creates a new instance of the object? A. Oe('Animal'); B. new Animal('large', 10); C. Otype(Animal); D. O(Animal); - answerANSWER: B. new Animal('large', 10); Additional Info: A. The create method needs the object name without quotes. C. This is an incorrect way to use a prototype. Prototypes are used to add methods to existing constructors. D. This is not the correct way to use the new keyword. It is not a method. A developer wants to use a module called DatePrettyPrint. This module exports one default function called printDate(). How can a developer import and use the printDate() function? A. import printDate() from '/path/DatePrettyP'; printDate(); B. import printDate from '/path/DatePrettyP';