When to Use Dot Notation to Access Object Properties in JavaScript?

Dot notation can be used to access a JavaScript object property whose identifier name:

  • Has unicode letters, $, _, or digits (0-9);
  • Does not start with a digit.

For example:

const obj = { foo123: 'bar', $foo: 'baz', _foo_: 'qux' };

console.log(obj.foo123); // 'bar'
console.log(obj.$foo); // 'baz'
console.log(obj._foo_); // 'qux'
const obj = { '123foo': 'bar' };

// SyntaxError

If you wish to access a property that starts with a number, a property that has a hyphen or space, or a dynamic property, then you can use the bracket notation to access object property instead.

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