如何检查我推入对象的对象数组是否具有来自另一个对象数组的特定键值

Question

这是我到目前为止所拥有的以及我已经尝试过的：

groceryList = [];

ngOnInit() {
  this._recipesSub = this.recipesService.recipes.subscribe((receivedData) => {
    this.loadedRecipes = receivedData.recipes;
  });
}
onCheckRecipe(e) {
    if (e.detail.checked === true) {
      let tickedRecipe = e.detail.value;
      let selectedRecipeIngredients;
      for (let recipe of this.loadedRecipes) {
        if (recipe.name === tickedRecipe) {
          selectedRecipeIngredients = recipe.ingredients;
        }
      }
      for (let selectedIng of selectedRecipeIngredients) {
        for (let existingIng of this.groceryList) {
          if (selectedIng.name) {
            this.groceryList.push(selectedIng);
          }
        }
      }
      console.log(this.groceryList);
    }
  }

这是我在控制台中收到的内容：

(8) [{…}, {…}, {…}, {…}, {…}, {…}, {…}, {…}]
0: {_id: "5f64ac1eb227fea1f63a5c99", name: "chia seeds", quantity: "10g"}
1: {_id: "5f64ac1eb227fea1f63a5c9a", name: "cherries", quantity: "15g"}
2: {_id: "5f64ac1eb227fea1f63a5c9b", name: "honey", quantity: "30g"}
3: {_id: "5f64ac1eb227fea1f63a5c9c", name: "almond flour", quantity: "10g"}
4: {_id: "5f64ac1eb227fea1f63a5c9e", name: "almond flour", quantity: "10g"}
5: {_id: "5f64ac1eb227fea1f63a5c9f", name: "egg", quantity: "10g"}
6: {_id: "5f64ac1eb227fea1f63a5ca0", name: "unsalted butter", quantity: "30g"}
7: {_id: "5f64ac1eb227fea1f63a5ca1", name: "peanut butter", quantity: "50g"}
length: 8
__proto__: Array(0)

并且我想要的结果不是name: "almond flour"两次，因为它已经在数组中，所以我可以只添加名称值不存在的对象：

相反的3： {_id: "5f64ac1eb227fea1f63a5c9c", name: "almond flour", quantity: "10g"}, {_id: "5f64ac1eb227fea1f63a5c9e", name: "almond flour", quantity: "10g"}是{_id: "5f64ac1eb227fea1f63a5c9e", name: "almond flour", quantity: "20g"}

我想要实现的是将每个成分添加到我的groceryList数组中，仅当该成分不存在并且存在时才将该成分的数量添加到现有键中。 例如，如果我有成分{_id: "5f64ac1eb227fea1f63a5c99", name: "chia seeds", quantity: "10g"}只添加数量而不是在我的groceryList创建一个新的成分groceryList

我不知道采取什么方法.. 如果你们有任何想法，我将不胜感激。

** 还有删除选项

onCheckRecipe(e) {
    if (e.detail.checked === true) {
      for (let recipe of this.loadedRecipes) {
        if (recipe.name === e.detail.value) {
          recipe.ingredients.forEach((eachIngredient) => {
            let matchedIng = this.groceryList.find(function (foundIng) {
              return foundIng.name === eachIngredient.name;
            });
            if (matchedIng) {
              matchedIng.quantity =
                matchedIng.quantity + eachIngredient.quantity;
            } else {
              this.groceryList.push(eachIngredient);
            }
          });
        }
      }
    } else {
      for (let recipe of this.loadedRecipes) {
        if (recipe.name === e.detail.value) {
          recipe.ingredients.forEach((element) => {
            let matched = this.groceryList.find(function (foundIngre) {
              return foundIngre.name === element.name;
            });
            if (matched.quantity === element.quantity) {
              let index = this.groceryList.findIndex(
                (x) => x.name === matched.name
              );
              this.groceryList.splice(index, 1);
            } else {
              matched.quantity = matched.quantity - element.quantity;
            }
          });
        }
      }
    }
  }

Answer 1

循环遍历成分数组并使用Array.prototype.find()查找每次迭代的匹配项。 如果存在，则更新数量，否则将成分对象推入数组

简化计算的一个建议是为单位添加另一个字段并将数量存储为数字，这样您就不需要为了做简单的数学运算而从字符串中解析单位

 const ingredients = [{_id: "5f64ac1eb227fea1f63a5c9e", name: "almond flour", quantity: "10g"}]; ingredients.forEach(ingr => { // returns matching object or undefined const wanted = data.find(({_id}) => _id === ingr._id); if(wanted){ const {quantity: wq} = wanted, units = wq.match(/\\D+/)[0]; wanted.quantity = parseInt(wq) + parseInt(ingr.quantity) + units; }else{ data.push(obj) } }) console.log(data)

 .as-console-wrapper {max-height: 100%!important;top:0;}

 <script> const data = [{_id: "5f64ac1eb227fea1f63a5c99", name: "chia seeds", quantity: "10g"}, {_id: "5f64ac1eb227fea1f63a5c9a", name: "cherries", quantity: "15g"}, {_id: "5f64ac1eb227fea1f63a5c9b", name: "honey", quantity: "30g"}, {_id: "5f64ac1eb227fea1f63a5c9e", name: "almond flour", quantity: "10g"}, {_id: "5f64ac1eb227fea1f63a5c9f", name: "egg", quantity: "10g"}, {_id: "5f64ac1eb227fea1f63a5ca0", name: "unsalted butter", quantity: "30g"}, {_id: "5f64ac1eb227fea1f63a5ca1", name: "peanut butter", quantity: "50g"}] </script>

Answer 2

这是我的解决方案，希望对您有所帮助：

const data = [
  { _id: "5f64ac1eb227fea1f63a5c99", name: "chia seeds", quantity: "10g" },
  { _id: "sdf7687hkksjj8881zzaooPP", name: "peanut butter", quantity: "20g" },
  { _id: "abcf781eb227fea1f63a5c9a", name: "cherries", quantity: "15g" },
  { _id: "5f64ac1eb227fea1f63a5c9b", name: "honey", quantity: "30g" },
  { _id: "5f64ac1eb227fea1f63a5c9c", name: "almond flour", quantity: "10g" },
  { _id: "5f64ac1eb227fea1f63a5c9e", name: "almond flour", quantity: "10g" },
  { _id: "5f64ac1eb227fea1f63a5c9f", name: "egg", quantity: "10g" },
  { _id: "ghg990c1eb227fea1f63a5c7", name: "egg", quantity: "19g" },
  { _id: "dsfsdffer340fea1f63a5ca0", name: "unsalted butter", quantity: "30g" },
  { _id: "5f64ac1eb227fea1f63a5ca1", name: "peanut butter", quantity: "50g" }
];

const groceryList = data.reduce(
  (acc, value) => {
    const index = acc.findIndex(elt => elt.name === value.name);
    if (index !== -1) {
      const accQuantity = acc[index].quantity;
      const valueQuantity = value.quantity;
      const unit = accQuantity.match(/\D+/)[0];
      acc[index].quantity = +accQuantity.match(/\d+/)[0] + +valueQuantity.match(/\d+/)[0] + unit;
    } else {
      acc.push(value);
    }
    return acc;
  }, []
);
console.log(groceryList);