Quick JavaScript Crash Course - Modern and Advanced JavaScript - Nullish-Coalescing-Operator

The lecture introduces the knowledge coalescing operator, a feature in JavaScript ES2020, which helps handle cases where properties might be undefined or have default values like zero or blank strings. The operator is demonstrated using a user object with properties like ID and email. It addresses issues with default values in JavaScript, providing a more predictable way to handle such scenarios. The lecture concludes with a brief preview of the next topic.

What is the primary purpose of the nullish coalescing operator in JavaScript?

• To handle undefined properties in objects

• To perform arithmetic operations

• To concatenate strings

• To sort arrays

Why might using the logical OR operator be problematic when setting default values?

• It cannot handle undefined values

• It only works with numbers

• It always returns true

• It treats falsy values like empty strings and zero as false

What issue arises when using logical OR with a blank string?

• It throws an error

• It appends the default value to the string

• It converts the string to a number

• It returns the default value instead of the blank string

In which version of ECMAScript was the nullish coalescing operator introduced?

• ES2020

• ES2021

• ES2018

• ES2015

How does the nullish coalescing operator improve handling of zero and empty strings?

• By treating them as valid values instead of falsy

• By converting them to true

• By ignoring them completely

• By converting them to null