Should I Use Quotes for Object Keys in JavaScript?

The Role of Quotes in Object Key Names

In JavaScript, objects are collections of key-value pairs. The keys are typically strings representing property names. You may encounter object keys written with or without quotation marks.

Does it Make a Difference?

No, enclosing object keys in quotation marks generally makes no difference. However, there is one exception: keys that are not valid JavaScript identifiers.

Valid vs. Invalid Identifiers

JavaScript identifiers must adhere to specific rules, such as starting with a letter or an underscore. If a key is not a valid identifier (e.g., it contains a hyphen), it must be enclosed in quotation marks.

Example:

// Invalid key without quotes
const obj1 = {foo-bar: 'value'}; // Error

// Valid key with quotes
const obj2 = {'foo-bar': 'value'}; // Correct

When to Use Quotes

Besides handling invalid identifiers, using quotation marks can enhance code readability, particularly for long or complex key names. It can also help avoid confusion when keys contain special characters like spaces or periods.

Note on JSON

While object keys in JavaScript can be either quoted or unquoted, JSON (JavaScript Object Notation) requires double quotes around keys for data exchange.

The above is the detailed content of Should I Use Quotes for Object Keys in JavaScript?. For more information, please follow other related articles on the PHP Chinese website!