Question

我知道这是我应该知道的东西，但是我很难弄清楚。

const food = {
  "design": [
    {
      "forTemperature": {
        "high": "100",
        "low": "70"
      },
      "productURL": "",
      "imageURL": ""
    },
    {
      "forTemperature": {
        "high": "80",
        "low": "65"
      },
      "productURL": "",
      "imageURL": ""
    },
    {
      "forTemperature": {
        "high": "75",
        "low": "65"
      },
      "productURL": "",
      "imageURL": ""
    },
    {
      "forTemperature": {
        "high": "67",
        "low": "60"
      },
      "productURL": "",
      "imageURL": ""
    }
  ]
}

我有基本的json文件，对象在数组中，但执行类似操作：

food.design.map((item, i) => i

对我不起作用。

我需要采取什么方法？

import food from "./apiDesign.json";


const New = props => {

  const [food, setFood] = useState([]);

  useEffect(() => {

    const fetchAPI = async e => {
      const designer = await food;
      setFood(designer);
    };

    fetchAPI();

  }, [])

  const stuff = () => {
    return loop // I was trying to loop it in here
  };

  return (
    {stuff}
  )
}

export default New;

Answer 1

这对我来说很好，因为您可以看到它正确地遍历了数组。你怎么了？

const food = {
  "design": [
    {
      "forTemperature": {
        "high": "100",
        "low": "70"
      },
      "productURL": "",
      "imageURL": ""
    },
    {
      "forTemperature": {
        "high": "80",
        "low": "65"
      },
      "productURL": "",
      "imageURL": ""
    },
    {
      "forTemperature": {
        "high": "75",
        "low": "65"
      },
      "productURL": "",
      "imageURL": ""
    },
    {
      "forTemperature": {
        "high": "67",
        "low": "60"
      },
      "productURL": "",
      "imageURL": ""
    }
  ]
}

food.design.map((item, i) => console.log(i, item))

Answer 2

下面的方法将返回 food.design 中的每个对象：

food.design.map(item => { /* do something here */ });

Answer 3

如果您使用的是ECMA Script 6，请使用此版本

const food = {
  "design": [
    {
      "forTemperature": {
        "high": "100",
        "low": "70"
      },
      "productURL": "",
      "imageURL": ""
    },
    {
      "forTemperature": {
        "high": "80",
        "low": "65"
      },
      "productURL": "",
      "imageURL": ""
    },
    {
      "forTemperature": {
        "high": "75",
        "low": "65"
      },
      "productURL": "",
      "imageURL": ""
    },
    {
      "forTemperature": {
        "high": "67",
        "low": "60"
      },
      "productURL": "",
      "imageURL": ""
    }
  ]
}
const obj =  food.design;
for (const key of Object.keys(obj)) {
    console.log(key, obj[key]);
}

遍历JavaScript中的对象

3 个答案: