JS-Dev-101 Salesforce Certified JavaScript Developer I Practice Questions

constructor(name) { super(name); this.role = 'Manager'; }

function Manager(name) { Employee.call(this, name); }

constructor(name) { this.role = 'Manager'; }

constructor(name) { this.name = name; super(); }

42

TypeError: Cannot read property 'value' of undefined

null

undefined

Object.create(null)

Object.assign({}, null)

{}

new Object(null)

They do not have the arguments object.

They are always hoisted to the top of the scope.

They can be used as constructors with the new keyword.

They do not have their own this binding.

export default function main() { ... } export function util() { ... }

export function main() { ... } export default util;

module.exports = main; exports.util = util;

export = main;

transactions.forEach((curr) => { let total = 0; return curr.type === 'credit' ? total + curr.amount : total - curr.amount })

transactions.map((acc, curr) => curr.type === 'credit' ? acc + curr.amount : acc - curr.amount, 0)

transactions.reduce((acc, curr) => curr.type === 'credit' ? acc + curr.amount : acc - curr.amount, 0)

transactions.filter((acc, curr) => curr.type === 'credit' ? acc + curr.amount : acc - curr.amount)

Loop variables are always global in JavaScript regardless of the keyword used.

Variables declared with var have block scope and are hoisted to the top of the block.

Variables declared with var have function scope and are not limited to the block in which they are defined.

The variable was implicitly declared as a global variable because strict mode was not enabled.

let unique = [...new Set(rawArray)];

let unique = Object.keys(Object.fromEntries(rawArray.map(id => [id, id])));

let unique = rawArray.map(item => item);

let unique = rawArray.filter((item, index) => rawArray.indexOf(item) === index);