在不改變原始JSON的情況下從GET請求中替換鍵值對

請原諒我，因為我仍然了解 JSON 和路由。我的任務是按配方名稱回傳一些物件，并包含其成分串列以及用“numSteps”鍵值對替換指令的物件：count_of_instruction_steps。我很難洗掉結果的“說明”鍵。這是我問過的另一個問題的延續。

食譜的 JSON 資料：

{
  "recipes": [
    {
      "name": "scrambledEggs",
      "ingredients": [
        "1 tsp oil",
        "2 eggs",
        "salt"
      ],
      "instructions": [
        "Beat eggs with salt",
        "Heat oil in pan",
        "Add eggs to pan when hot",
        "Gather eggs into curds, remove when cooked",
        "Salt to taste and enjoy"
      ]
    },
    {
      "name": "garlicPasta",
      "ingredients": [
        "500mL water",
        "100g spaghetti",
        "25mL olive oil",
        "4 cloves garlic",
        "Salt"
      ],
      "instructions": [
        "Heat garlic in olive oil",
        "Boil water in pot",
        "Add pasta to boiling water",
        "Remove pasta from water and mix with garlic olive oil",
        "Salt to taste and enjoy"
      ]
    },
    {
      "name": "chai",
      "ingredients": [
        "400mL water",
        "100mL milk",
        "5g chai masala",
        "2 tea bags or 20 g loose tea leaves"
      ],
      "instructions": [
        "Heat water until 80 C",
        "Add milk, heat until 80 C",
        "Add tea leaves/tea bags, chai masala; mix and steep for 3-4 minutes",
        "Remove mixture from heat; strain and enjoy"
      ]
    }
  ]
}

任務：回傳的 GET 請求http://localhost:3000/recipes/details/garlicPasta：如果配方存在：

Response body (JSON):
{
    "details":
        {
            "ingredients": [
                "500mL water",
                "100g spaghetti",
                "25mL olive oil",
                "4 cloves garlic",
                "Salt"
            ],
            "numSteps":5
        }
}
Status: 200

如果配方不存在：

Response body (JSON): {}
Status: 200

我實際得到的：

{
  name: "garlicPasta",
  ingredients: [
  "500mL water",
  "100g spaghetti",
  "25mL olive oil",
  "4 cloves garlic",
  "Salt"
 ],
 instructions: {
  numSteps: 5
  }
}

我的代碼：

app.get('/recipes/details/:name', (req, res) => {
  let count = 0
  const numSteps = {}
  const recipe = recipes.find(r => r.name === req.params.name)
  const instructions = recipes.map(r => {
    if(r.name === req.params.name){
      for(let instruction of r.instructions){
          count  = 1
      }
    }
  })
  recipe.instructions = {"numSteps": count}
  res.status(200).send(recipe);
})

uj5u.com熱心網友回復：

我不會嘗試回傳修改后的“配方”物件，因為您需要的回應形狀不同。您可以使用現有代碼找到正確的配方，然后只需創建一個具有所需回應屬性的新物件。請注意，您可以只使用 recipe.instructions.length 來了解有多少步驟。

app.get('/recipes/details/:name', (req, res) => {
  let count = 0;
  const recipe = recipes.find(r => r.name === req.params.name);
  
  const output = {
    details: {
      ingredients: recipe.ingredients,
      numSteps: recipe.instructions.length
    }
  };
  
  res.status(200).send(output);
})

uj5u.com熱心網友回復：

您不是在創建details屬性，而是instructions在結果中添加了您不想要的屬性。

無需回圈計數numSteps，您只需使用r.instructions.length. 并且一旦找到帶有 的食譜recipes.find()，就不需要另一個回圈來查找食譜名稱。

您沒有檢查是否可以找到配方，因此您{}在這種情況下回傳。

app.get('/recipes/details/:name', (req, res) => {
  const recipe = recipes.find(r => r.name === req.params.name);
  let result = {};
  if (recipe) {
    result.details = {
      ingredients: recipe.ingredients,
      numSteps: recipe.instructions.length
    };
  }
  res.status(200).send(recipe);
})

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