Redux Example — React Technical Interview Questions & Answers

Redux Example

Redux Example

  • Tiny example: cart reducer. state is a string[]. action { type: 'cart/add', payload: 'Pen' }. return [...state, action.payload]. Never state.push. Dispatch from a button. The screen lists the array. Same pattern as a counter: inc action, n+1.
  • Walk dispatch → reducer → new store → React-Redux useSelector re-render. That four-step dry run is the ‘Redux example’ viva.
  • Redux Example — output: Pen. payload is the item. Spread a new array — don’t push on state.
  view click
      │ dispatch
      ▼
   reducer
      │ new state
      ▼
     store → UI

Technical Interview Tip: One add-to-cart reducer on the board.

Code Examples for Redux Example

Example

// Redux cart
const add = { type: "cart/add", payload: "Pen" };
function cart(state = [], action) {
  if (action.type === "cart/add") return [...state, action.payload];
  return state;
}
console.log(cart([], add).join(","));

Redux Example — output: Pen. payload is the item. Spread a new array — don’t push on state.

How to Explain Redux Example to an Interviewer

Explain Redux Example as if you are teaching a junior — definition, then one tiny UI.

Action : type + payload. Reducer : copy, don’t mutate.

What does the example show on screen (or print), and what does that prove?

Redux Example — output: Pen

What mistake do freshers make with Redux Example?

Reducer : copy, don’t mutate.