React · Theory

React Component API

Theory

17/94

React Component API

Component API means the methods React gives a class: setState, forceUpdate, render. setState merges object state (shallow) and schedules render. forceUpdate re-renders without changing state — almost never needed; it’s a smell.

Hooks world: useState / useReducer replace setState. There is no forceUpdate. If a fresher recites forceUpdate as daily API, steer them back to ‘fix the state, don’t force paint’.

React Component API — output — class vs hooks. Interview: name setState, then say we use useState now.

Diagram

Parent
    │ props (read-only)
    ▼
  Child → UI

Exam tip

setState vs useState. Avoid forceUpdate.

Example

// Component API
console.log("class : this.setState / this.forceUpdate");
console.log("hooks : useState / useReducer");
console.log("don't : call setState in render forever");

React Component API — output: class vs hooks. Interview: name setState, then say we use useState now.

Short notes

Class : setState, render, rare forceUpdate.
Hooks : useState / useReducer.
TrapforceUpdate as a habit.

React · Theory

React Component API

← All stacks

Theory

17/94

React Component API

Hooks world: useState / useReducer replace setState. There is no forceUpdate. If a fresher recites forceUpdate as daily API, steer them back to ‘fix the state, don’t force paint’.

React Component API — output — class vs hooks. Interview: name setState, then say we use useState now.

Diagram

Parent
    │ props (read-only)
    ▼
  Child → UI

Exam tip

setState vs useState. Avoid forceUpdate.

Example

// Component API
console.log("class : this.setState / this.forceUpdate");
console.log("hooks : useState / useReducer");
console.log("don't : call setState in render forever");

React Component API — output: class vs hooks. Interview: name setState, then say we use useState now.

Short notes

Class : setState, render, rare forceUpdate.
Hooks : useState / useReducer.
TrapforceUpdate as a habit.

React Component API

Example

Short notes

Questions

React Component API

Example

Short notes

Questions