Mutable vs immutable objects
Mutable objects can change in place; immutable objects require a new object for a changed value.
- List and dict are mutable
- str and tuple are immutable
- Matters for side effects and hashing
Mutable vs immutable objects
Tagged with objects
6 cards
Shallow copy vs deep copy
A shallow copy copies the outer container; a deep copy recursively copies nested objects too.
- Shallow shares nested refs
- Deep duplicates nested refs
- copy and deepcopy from copy module
Shallow copy vs deep copy
Object creation, object literals, property access, dot vs bracket notation, and object methods
Objects can be created in several ways, and property access depends on whether the key is static or dynamic.
- Object literals are the common default
- Dot access needs a valid identifier
- Bracket access handles dynamic keys
Object creation, object literals, property access, dot vs bracket notation, and object methods
Object.keys, Object.values, Object.entries, Object.assign, spread with objects, shallow copy vs deep copy, Object.freeze, and Object.seal
Object helpers are useful for inspection and copying, but most built-in copy patterns are still shallow.
- `Object.assign` and spread are shallow
- `freeze` and `seal` change mutability rules
- Entries are useful for iteration
Object.keys, Object.values, Object.entries, Object.assign, spread with objects, shallow copy vs deep copy, Object.freeze, and Object.seal
Property descriptors, getters and setters, Object.create, hasOwnProperty, and the in operator
JavaScript objects support descriptor-level control, computed accessors, explicit prototype creation, and different ways to check for properties.
- Descriptors control writability and enumerability
- Getters and setters run code on access
- `in` and `hasOwnProperty` answer different questions
Property descriptors, getters and setters, Object.create, hasOwnProperty, and the in operator
Spread operator, rest operator, and destructuring assignment in JavaScript
Spread expands values, rest collects remaining values, and destructuring pulls parts of arrays or objects into variables.
- Spread copies one level deep
- Rest gathers leftovers
- Destructuring works with arrays and objects
Spread operator, rest operator, and destructuring assignment in JavaScript