如果值已存在，则ES6数组推送与合并

Question

我正在创建一个基于食谱的购物车。

this.shoppingCartRecipes.forEach(recipe => {
      recipe.ingredients.forEach(ingredient => {
        this.shoppingCart.push({
          amount: ingredient.amount,
          unit: ingredient.unit,
          name: ingredient.ingredient,
          isDone: ingredient.isDone || false,
          recipeID: recipe.id
        });
      });
    });

但是，如果配料名称和配料单位相同，我希望合并这些值。有没有一种聪明的方法可以做到这一点？

Answer 1

如果将this.shoppingCart保留为数组：

this.shoppingCartRecipes.forEach(recipe => {
  recipe.ingredients.forEach(ingredient => {
    const shoppingCartIngredient = this.shoppingCart.find( item => (
      (item.name === ingredient.ingredient) && (item.unit === ingredient.unit)
    ))

    // If the ingredient exists, just update it
    if (shoppingCartIngredient) {
      shoppingCartIngredient.amount = ingredient.amount;
      shoppingCartIngredient.isDone = ingredient.isDone || false;
      shoppingCartIngredient.recipeID = recipe.id;
    } else {
      // Otherwise create a new record
      this.shoppingCart.push({
        amount: ingredient.amount,
        unit: ingredient.unit,
        name: ingredient.ingredient,
        isDone: ingredient.isDone || false,
        recipeID: recipe.id
      });
    }
  });
});

Answer 2

您可以使用` `lodash‘库：

推流后使用_.uniq(array);或_.uniqBy(array);。