An example using array .map()

arraymap.js

{questions.map((question, index) => (
          <Card
            key={index}
            question={question.question}
            answer={question.answer}
            index={index}
          />
        ))}

{Object.keys(decks).map(key => {
          const { title, uuid, questions } = decks[key];
          return (
            <View key={uuid}>
              <Text>{title}</Text>
              <Text>{questions.length}</Text>
            </View>
          );
        })}
JSON.stringify(this.state)
render() {
    const metaInfo = getMetricMetaInfo()

    return (
      <View>
        {Object.keys(metaInfo).map((key) => {
          const { getIcon, type, ...rest } = metaInfo[key]
          const value = this.state[key]

          return (
            <View key={key}>
              {getIcon()}
              {type === 'slider'
                ? <UdaciSlider
                    value={value}
                    onChange={(value) => this.slide(key, value)}
                    {...rest}
                  />
                : <UdaciSteppers
                    value={value}
                    onIncrement={() => this.increment(key)}
                    onDecrement={() => this.decrement(key)}
                    {...rest}
                  />}
            </View>
          )
        })}
      </View>
    )
  }
 sortPostsByCategory = (category) => {
      this.setState({sortBy: category})
      const newObj = {};
      Object.keys(initialPosts).map((post) => {
        if(initialPosts[post]['category'] === category) {
          newObj[post] = initialPosts[post]
        }
      })
      this.setState({posts: newObj})

    }