isEmpty()

isEmpty(value): boolean

Checks if value is empty (object, array, string, Map, or Set).

note

Primitives (numbers, booleans) and null/undefined return true.

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Parameters

value: unknown

The value to check.

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Returns: boolean

true if value is empty, false otherwise.

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Since

2.0.0

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Performance

O(1) for primitives/null/undefined/arrays/strings/Map/Set via early returns and native properties. O(n) for objects due to Object.keys().

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Example

isEmpty([]);           // => true
isEmpty([1, 2]);       // => false
isEmpty({});           // => true
isEmpty({ a: 1 });     // => false
isEmpty('');           // => true
isEmpty('abc');        // => false
isEmpty(new Map());    // => true
isEmpty(new Set([1])); // => false
isEmpty(null);         // => true
isEmpty(42);           // => true (primitives are "empty")

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How it works?

Checks if a value is empty (arrays, objects, strings, Map, Set).

Examples

Value	Result
[]	true
[1, 2]	false
{}	true
{ a: 1 }	false
''	true
'abc'	false
new Map()	true
new Set([1])	false
null	true
42	true (primitives are "empty")

Use Case: Form Validation

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Use Cases

Check for empty collections 📌

Verify if an array, object, string, or collection is empty. Essential for validating data completeness before processing.

#check#empty#collections#validation#completeness#data

if (isEmpty(data)) {
  return null; // Handle empty state
}

Validate form inputs

Ensure required fields are not empty strings. Critical for user input validation.

#validate#forms#inputs#required#fields#user-input

if (isEmpty(username.trim())) {
  showError("Username is required");
}

Guard against processing empty data

Early return when collections have no items to process. Prevents unnecessary operations and potential errors.

#guard#empty#processing#early-return#safety#validation

function sendNotifications(users: User[]) {
  if (isEmpty(users)) {
    console.log("No users to notify");
    return;
  }
  
  // Safe to process - we have users
  users.forEach(user => notify(user));
}