➕optional invocation ?.()

🚧 under construction -> flowchart

• JS ⟩ statement ⟩ expression ⟩ operator ⟩ optional chaining ⟩ optional invocation ?.()

• JS ⟩ value ⟩ object ⟩ property ⟩ access ⟩ optional invocation ?.()

(⭐️ ES2020) (🌟 chaining rules | table of operators )

f?.(args) returns undefined if f is nullish.

🈯 synonyms："conditional invocation", "optional invocation"

🗺️ 圖表

🧨 雷區

f ?.()

• only checks whether f is nullish❗

• does not verify that f is actually a function❗

👥

• 🌟chaining rules
• conditional operator (?:)

• dot notation (.)

• bracket notation []

• ℹ️question dot (?.) / parentheses () punctuators are used in this operator.

💈

📗

• JS.info ⟩ Optional chaining '?.'
• freeCodeCamp ⟩ 10 New JavaScript Features in ES2020 That You Should Know
• JavaScript: The Definitive Guide ⟩ 4.5.1 Conditional Invocation

📘

• Optional chaining (?.)

🚧

• flowchart

• example