I can't seem to get my head around the array.reduce() function. I've got the following array:
orders = [{
"id": 4930,
"status": "pending",
"line_items": [
{
"item_name": "Crepe",
"item_qty": 2,
"recipe": [
{
"ing_name": "Flour",
"ing_qty": "120",
"ing_unit": "g"
},
{
"ing_name": "Milk",
"ing_qty": "100",
"ing_unit": "ml"
},
{
"ing_name": "Egg",
"ing_qty": "2",
"ing_unit": "each"
}
]
},
{
"item_name": "Pancake",
"item_qty": 3,
"recipe": [
{
"ing_name": "Flour",
"ing_qty": "120",
"ing_unit": "g"
},
{
"ing_name": "Milk",
"ing_qty": "100",
"ing_unit": "ml"
},
{
"ing_name": "Egg",
"ing_qty": "2",
"ing_unit": "each"
},
{
"ing_name": "Sugar",
"ing_qty": "10",
"ing_unit": "g"
}
]
}
]
},
{
"id": 4927,
"status": "pending",
"line_items": [
{
"item_name": "Pancake",
"item_qty": 2,
"recipe": [
{
"ing_name": "Flour",
"ing_qty": "120",
"ing_unit": "g"
},
{
"ing_name": "Milk",
"ing_qty": "100",
"ing_unit": "ml"
},
{
"ing_name": "Egg",
"ing_qty": "2",
"ing_unit": "each"
},
{
"ing_name": "Sugar",
"ing_qty": "10",
"ing_unit": "g"
}
]
}
]
}];
and I'm trying to get a result like below. I'm not sure how to go about multiplying the ingredient amounts with the item quantities:
"total_ingredients": [{
"ing_name": "Flour",
"ing_qty": "840",
"ing_unit": "g"
},
{
"ing_name": "Milk",
"ing_qty": "700",
"ing_unit": "ml"
},
{
"ing_name": "Egg",
"ing_qty": "14",
"ing_unit": "each"
},
{
"ing_name": "Sugar",
"ing_qty": "20",
"ing_unit": "g"
}
];
I've tried following the structure that was given here but the arrow function is throwing me off. Any sort of help would be greatly appreciated.
CodePudding user response：
Read about reduce. It's awesome. About this one, let me explain.
We start with this skeleton, preparing to group by some property:
orders.reduce(function(agg, order) {
agg[order["some_property"]] = order;
return agg;
}, {})
That's the idea!
Anyway, for each of these, we iterate the list of recipes and products, with the idea to collect instead of "some_property" the actual "ing_name". While we group, we calculate the total. Finally, Object.values() will remove the keys we grouped by and turn it into the required array.
var orders = [{
"id": 4930,
"status": "pending",
"line_items": [{
"item_name": "Crepe",
"item_qty": 2,
"recipe": [{
"ing_name": "Flour",
"ing_qty": "120",
"ing_unit": "g"
},
{
"ing_name": "Milk",
"ing_qty": "100",
"ing_unit": "ml"
},
{
"ing_name": "Egg",
"ing_qty": "2",
"ing_unit": "each"
}
]
},
{
"item_name": "Pancake",
"item_qty": 3,
"recipe": [{
"ing_name": "Flour",
"ing_qty": "120",
"ing_unit": "g"
},
{
"ing_name": "Milk",
"ing_qty": "100",
"ing_unit": "ml"
},
{
"ing_name": "Egg",
"ing_qty": "2",
"ing_unit": "each"
},
{
"ing_name": "Sugar",
"ing_qty": "10",
"ing_unit": "g"
}
]
}
]
},
{
"id": 4927,
"status": "pending",
"line_items": [{
"item_name": "Pancake",
"item_qty": 2,
"recipe": [{
"ing_name": "Flour",
"ing_qty": "120",
"ing_unit": "g"
},
{
"ing_name": "Milk",
"ing_qty": "100",
"ing_unit": "ml"
},
{
"ing_name": "Egg",
"ing_qty": "2",
"ing_unit": "each"
},
{
"ing_name": "Sugar",
"ing_qty": "10",
"ing_unit": "g"
}
]
}]
}
];
total_ingredients =
Object.values(orders.reduce(function(agg, order) {
order.line_items.forEach(function(item) {
item.recipe.forEach(function(product) {
agg[product.ing_name] = agg[product.ing_name] || {
ing_name: product.ing_name,
ing_qty: 0,
ing_unit: product.ing_unit
}
agg[product.ing_name].ing_qty = Number(agg[product.ing_name].ing_qty) Number(product.ing_qty)
})
})
return agg;
}, {}))
console.log({
total_ingredients: total_ingredients
})CodePudding user response：
Thank you to @IT Goldman and @NinaScholz for the prompt responses.
I'm sure there's probably a more elegant way of solving this, but I've come up with something that works.
var orders = [{
"id": 4930,
"status": "pending",
"line_items": [{
"item_name": "Crepe",
"item_qty": 2,
"recipe": [{
"ing_name": "Flour",
"ing_qty": "120",
"ing_unit": "g"
},
{
"ing_name": "Milk",
"ing_qty": "100",
"ing_unit": "ml"
},
{
"ing_name": "Egg",
"ing_qty": "2",
"ing_unit": "each"
}
]
},
{
"item_name": "Pancake",
"item_qty": 3,
"recipe": [{
"ing_name": "Flour",
"ing_qty": "120",
"ing_unit": "g"
},
{
"ing_name": "Milk",
"ing_qty": "100",
"ing_unit": "ml"
},
{
"ing_name": "Egg",
"ing_qty": "2",
"ing_unit": "each"
},
{
"ing_name": "Sugar",
"ing_qty": "10",
"ing_unit": "g"
}
]
}
]
},
{
"id": 4927,
"status": "pending",
"line_items": [{
"item_name": "Pancake",
"item_qty": 2,
"recipe": [{
"ing_name": "Flour",
"ing_qty": "120",
"ing_unit": "g"
},
{
"ing_name": "Milk",
"ing_qty": "100",
"ing_unit": "ml"
},
{
"ing_name": "Egg",
"ing_qty": "2",
"ing_unit": "each"
},
{
"ing_name": "Sugar",
"ing_qty": "10",
"ing_unit": "g"
}
]
}]
}
];
function sumIngredients(orders) {
total_ingredients = Object.values(orders.reduce(function(agg, order) {
// for each order do the following..
order.line_items.forEach(function(lineitem) {
// for each line item consolidate each item
agg[lineitem.item_name] = agg[lineitem.item_name] || {
item_name: agg[lineitem.item_name] == null ? lineitem.item_name : agg['item_name'] ', ' lineitem.item_name,
item_qty: 0
}
// and their quantities
agg[lineitem.item_name].item_qty = Number(agg[lineitem.item_name].item_qty) Number(lineitem.item_qty);
lineitem.recipe.forEach(function(ingredient) {
// for each ingredient in a line item, here's the new structure
agg[ingredient.ing_name] = agg[ingredient.ing_name] || {
ing_name: ingredient.ing_name,
ing_qty: 0,
ing_unit: ingredient.ing_unit
}
// consolidate ingredient quantities and multiply them with the line-item quantities
agg[ingredient.ing_name].ing_qty = Number(agg[ingredient.ing_name].ing_qty) Number(ingredient.ing_qty * Number(lineitem.item_qty))
})
})
return agg;
}, {}));
return total_ingredients;
};
var orders_arr = sumIngredients(orders);
console.log(orders_arr);Improvements/suggestions are most welcome :)