how to render array in object in array? (react)

Need to Return Your data like below!!

import React from "react";

export default function App() {


let checked = [{
  food:['apple', 'banana'],
  drink:['wine', 'beer']
}];

return (
  <div className="App">

 {
        checked.map((item) => {
        return item.food.map((fruit)=>{
        return <h1>{fruit}</h1>
           })
        })
 }
</div>

); }

Your code has multiple errors.

• It should be render instead of rander
• While defining object, multiple properties should be separated using a comma. So put comma after the food array.
• forEach doesn't return any thing. It just iterates over an array. So, if you want to return something (in this case a div element), use map.
• Also, you should use key for each div element otherwise react would give you a warning in the console. This is done so that while re-rendering, based on the keys, react would understand which component to re-render and which to skip. Otherwise all the div would be re-rendered which is a costly operation.

const checked = [
    {
        food: ["apple", "banana"],
        drink: ["wine", "beer"]
    }
]

return (
    <>
        {checked.map((value) => {
            return value.food.map((each, index) => {
                return <div key={index}>{each}</div>;
            });
        })}
    </>
);

There is a couple of improvements that require to be implemented to make the list displayed.

First, the map method does not return anything. Two solutions:

1. Remove the curly brackets checked.map((value) => value...
2. Add a return keyword: checked.map((value) => { return value...}

The other issue is that the second loop is iterated using the forEach method. The difference between the two (forEach and map) from MDN:

The forEach() method executes a provided function once for each array element. MDN

The map() method creates a new array populated with the results of calling a provided function on every element in the calling array. MDN

Basically, it means that forEach does not return anything and that why you need to use map

checked.map((value) => {
   return value.food.map((each) => (<div>{each}</div>))
})}

or

checked.map((value) =>
     value.food.map((each) => (<div>{each}</div>))
)}

You are iterating over the checked array items using forEach which won't induce any results since the forEach method

executes a provided function once for each array element.

which won't result in a transformed array.

What you are looking for is the map method which

creates a new array populated with the results of calling a provided function on every element in the calling array.

hence returning your transformed items so that they can be rendered (transformed at compilation time to ReactElement using the JSX syntax).

Note that you need to use an HTML tag instead of a React.Fragment the empty tag <> syntax:

const checked = [{
                  food:['apple', 'banana'], // there is a missing comma here
                  drink:['wine', 'beer']
                 }];

render ( // render and not rander
    <div> // div instead of empty tag
     {checked.map((item) => item.food.map((each) => <div>{each}</div>))} 
    </div>
    )

Can check this approach. if you want to print just food values, below code should work. If you want to print all the values (both food and drink), then uncomment the commented code below.

export default function App() {
  const checked = [
    {
      food: ["apple", "banana"],
      drink: ["wine", "beer"]
    },
    {
      food: ["grapes", "oranges"],
      drink: ["coke", "sprite"]
    }
  ];

  // to display values of all arrays.
  // return (
  //   <>
  //     {checked.map((value) => {
  //       const keys = Object.keys(value);
  //       return keys.map((eachKey) => {
  //         return value[eachKey].map((individualValue) =>
  //           (
  //             <div>{individualValue}</div>
  //           )
  //         )
  //       });
  //     })
  //     }
  //   </>
  // );

  // To display just food values.
  return (
    <>
      {checked.map((value) => {
        return value.food.map((each) => <div>{each}</div>);
      })}
    </>
  );
}