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

This is what I have so far and what I've and tried:

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);
    }
  }

This is what I receive in my console:

(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)

and my desire outcome is not to have name: "almond flour" twice because it was already in the array, so i can be able to add just the object that which name value doesn't exist already:

Instead of 3: {_id: "5f64ac1eb227fea1f63a5c9c", name: "almond flour", quantity: "10g"}, {_id: "5f64ac1eb227fea1f63a5c9e", name: "almond flour", quantity: "10g"} to be {_id: "5f64ac1eb227fea1f63a5c9e", name: "almond flour", quantity: "20g"}

What I want to achieve is to add to my groceryList array each Ingredient only if that ingredient is not present already and if it's present to add just the quantity of that ingredient to an existing key. For example if i have the ingredient {_id: "5f64ac1eb227fea1f63a5c99", name: "chia seeds", quantity: "10g"} to add just the quantity and not to create a new obj of ingredient in my groceryList

I am don't know what approach to take.. If you guys have any idea I would really appreciate it.

** Also the remove option

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

Loop over the ingredients array and use Array.prototype.find() to look for a match for each iteration. If one exists, update quantity, otherwise push ingredient object to the array

One suggestion to simplify the computation would be add another field for the units and store quantity as a number so you don't need to parse units from a string just to do the simple math

 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

This is my Solution, i hope that is helpful :

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);