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1The DOM Manipulation Problem Before React
2State-View Synchronization: The Core Challenge
3The jQuery Era and Its Limitations
4Imperative vs Declarative UI Updates
5The Problem of Shared Mutable State
6Event Listener Spaghetti Code
7The Performance Cost of Naive Re-rendering
8Component Reusability Before React
9Declarative UI: What vs How
10Component-Based Architecture
11Unidirectional Data Flow
12The Virtual DOM Concept
13Reconciliation: React's Diffing Algorithm
14Learn Once, Write Anywhere
15Composition Over Inheritance
16Explicit Over Implicit
17UI as a Function of State
18Progressive Adoption and Escape Hatches
19jQuery and the Imperative DOM Manipulation Era
20Backbone.js: MVC in the Browser
21Angular 1.x: Two-Way Binding and Digest Cycles
22Ember: Convention Over Configuration
23Vue: The Progressive Framework
24Angular (2+): TypeScript-First Architecture
25Svelte: Compile-Time Reactivity
26Solid: Fine-Grained Reactivity
27Web Components: Standards-Based Approach
28Preact: React's Lightweight Alternative
29Comparing Virtual DOM Implementations
30Ecosystem Size as a Decision Factor
31Static Content Sites: When a Framework is Overkill
32Simple Forms and Progressive Enhancement
33Performance-Critical Mobile Web Apps
34SEO-First Content Without SSR Infrastructure
35Teams Without JavaScript Expertise
36Embedding in Existing Non-React Apps

1The DOM Manipulation Problem Before React
2State-View Synchronization: The Core Challenge
3The jQuery Era and Its Limitations
4Imperative vs Declarative UI Updates
5The Problem of Shared Mutable State
6Event Listener Spaghetti Code
7The Performance Cost of Naive Re-rendering
8Component Reusability Before React
9Declarative UI: What vs How
10Component-Based Architecture
11Unidirectional Data Flow
12The Virtual DOM Concept
13Reconciliation: React's Diffing Algorithm
14Learn Once, Write Anywhere
15Composition Over Inheritance
16Explicit Over Implicit
17UI as a Function of State
18Progressive Adoption and Escape Hatches
19jQuery and the Imperative DOM Manipulation Era
20Backbone.js: MVC in the Browser
21Angular 1.x: Two-Way Binding and Digest Cycles
22Ember: Convention Over Configuration
23Vue: The Progressive Framework
24Angular (2+): TypeScript-First Architecture
25Svelte: Compile-Time Reactivity
26Solid: Fine-Grained Reactivity
27Web Components: Standards-Based Approach
28Preact: React's Lightweight Alternative
29Comparing Virtual DOM Implementations
30Ecosystem Size as a Decision Factor
31Static Content Sites: When a Framework is Overkill
32Simple Forms and Progressive Enhancement
33Performance-Critical Mobile Web Apps
34SEO-First Content Without SSR Infrastructure
35Teams Without JavaScript Expertise
36Embedding in Existing Non-React Apps

Lesson 2242 of 2,396·49. Performance: Identifying ProblemsPro lesson

Array Literals and .map() Return Values

How `items.map(item => ({ ...item }))` creates new objects and when it matters for child components.

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