Consider a scenario where you have an array of numbers, and you need to create a new array with only the numbers greater than 10. Which method would you use?
- filter
- map
- reduce
- forEach
In this scenario, the most suitable array method is filter. The filter method is designed for creating a new array containing elements that pass a certain condition. It allows you to filter out numbers greater than 10 effectively.
If you have a Symbol mySymbol, you can access its description using mySymbol.__________.
- name
- description
- valueOf
- toString
The correct property to access the description of a Symbol is description. The description property is used to get or set the description of a Symbol, providing additional information about the Symbol.
When a generator function is initially called, it returns a(n) __________ object.
- Generator
- Promise
- Iterator
- Iterable
When a generator function is called, it returns an iterator object. This object can be used to iterate through the values generated by the generator using the next() method. The other options do not represent the initial return type of a generator function.
How does ES6 support dynamic property names in object literals?
- Computed Property Names
- Object Linking
- Dynamic Key Binding
- Property Aliasing
ES6 supports dynamic property names through computed property names. By using square brackets around an expression within an object literal, you can create properties with names determined at runtime. This enhances the flexibility and expressiveness of object literals.
In a node.js application, how would you handle errors when performing multiple asynchronous operations in parallel?
- Implementing a try-catch block around each asynchronous operation
- Utilizing the Promise.all() method with a single catch block for error handling
- Using multiple catch blocks for each asynchronous operation
- Handling errors outside the asynchronous operations entirely
In the scenario of multiple asynchronous operations, using Promise.all() simplifies error handling by allowing a single catch block to capture errors from any of the parallel operations. This promotes cleaner and more concise error management, making it easier to identify and address issues in the asynchronous flow. Multiple catch blocks might lead to redundancy and make the code harder to maintain.
In the context of tree shaking, what is the significance of the "sideEffects" flag in a package.json file?
- Specifies files that should be excluded from the tree-shaking process
- Indicates whether the package has side effects that prevent tree shaking
- Determines the priority of modules during tree shaking
- Flags external dependencies for tree shaking
The "sideEffects" flag in package.json is used to inform the bundler about the side effects of a module. If set to false, it allows the bundler to perform aggressive tree shaking by eliminating unused exports. If set to true, it implies the module has side effects, and the bundler avoids tree shaking to maintain those side effects.
When importing a module without specifying a subpath, ES6 will by default look for a file named ________.
- main.js
- module.js
- index.js
- entry.js
If a specific subpath is not provided during the import, ES6 will default to looking for a file named index.js within the target module directory.
The method _________ is used to execute code after a Promise is either fulfilled or rejected.
- finally()
- done()
- complete()
- finalize()
The correct method is finally(). The finally() method is used to specify a function that will be executed regardless of whether the Promise is fulfilled or rejected. It allows you to perform cleanup or finalization tasks.
Tree shaking is most effective when modules use _______ exports rather than wildcard exports.
- Named
- Default
- All
- Individual
Tree shaking is a technique in JavaScript used to eliminate unused code during the build process. When modules use named exports, it allows the bundler to selectively include only the functions or variables that are actually used, making tree shaking more effective. Default exports and wildcard exports can complicate this process, leading to less efficient tree shaking.
If an arrow function is written with a single expression, the return value is the result of the expression without using the ________ keyword.
- Break
- Return
- Yield
- Exit
In arrow functions, if the function body consists of a single expression, you can omit the curly braces {} and the return keyword. The return value will be the result of the expression automatically.