I am using JSON path to do something similar to this:
I have copied the JSON path example, but modified the price field to represent price Year-over-Year (number to array).
{
"store": {
"book": [
{
"category": "reference",
"author": "Nigel Rees",
"title": "Sayings of the Century",
"price": [ 1, 2, 3 ]
},
{
"category" :"fiction",
"author": "Evelyn Waugh",
"title": "Sword of Honour",
"price": [ 1, 2, 3 ]
},
{
"category": "fiction",
"author": "Herman Melville",
"title": "Moby Dick",
"isbn": "0-553-21311-3",
"price": [ 1, 2, 3 ]
},
{
"category": "fiction",
"author": "J. R. R. Tolkien",
"title": "The Lord of the Rings",
"isbn": "0-395-19395-8",
"price": [ 1, 2, 3 ]
}
],
"bicycle": {
"color": "red",
"price": [ 1, 2, 3 ]
}
},
"expensive": 10
}
What I want to find is the year over year total price for all the books.
I can get a Array of Array (lets say res) using: $.store.book[*].price
Output:
[
[ 1, 2, 3 ],
[ 1, 2, 3 ],
[ 1, 2, 3 ],
[ 1, 2, 3 ]
]
I want to further reduce this output (by sum) to:
[4, 8, 12] // Sum up nth element of each array.
// (res[0][0] + res[1][0] + res[2][0] + res[3][0] = 4 ... and so on)
Is there a way to achieve this using jsonpath (preferred)/any other JavaScript syntax ?
let data = [
[ 1, 7, 3 ],
[ 2, 6, 3 ],
[ 3, 5, 3 ],
[ 4, 4, 3 ]
]
let result = data[0].map((_, colIndex) => data.map(row => row[colIndex]))
.map(value => value.reduce((acc, value) => acc + value, 0))
console.log(result) // [ 10, 22, 12 ]The first map transposes rows and columns, the second map sums up what after the transpose are the rows.
const data = {
"store": {
"book": [{
"category": "reference",
"author": "Nigel Rees",
"title": "Sayings of the Century",
"price": [1, 2, 3]
},
{
"category": "fiction",
"author": "Evelyn Waugh",
"title": "Sword of Honour",
"price": [1, 2, 3]
},
{
"category": "fiction",
"author": "Herman Melville",
"title": "Moby Dick",
"isbn": "0-553-21311-3",
"price": [1, 2, 3]
},
{
"category": "fiction",
"author": "J. R. R. Tolkien",
"title": "The Lord of the Rings",
"isbn": "0-395-19395-8",
"price": [1, 2, 3]
}
]
}
}
const prices = []
data.store.book.forEach(book => {
book.price.forEach((price, index) => {
if (!prices[index]) prices[index] = 0;
prices[index] += price;
})
})
console.log(prices)You can use some .map() and Array.prototype.reduce() paired with comma operator.
const a = { "store": { "book": [{ "category": "reference", "author": "Nigel Rees", "title": "Sayings of the Century", "price": [1, 2, 3] }, { "category": "fiction", "author": "Evelyn Waugh", "title": "Sword of Honour", "price": [1, 2, 3] }, { "category": "fiction", "author": "Herman Melville", "title": "Moby Dick", "isbn": "0-553-21311-3", "price": [1, 2, 3] }, { "category": "fiction", "author": "J. R. R. Tolkien", "title": "The Lord of the Rings", "isbn": "0-395-19395-8", "price": [1, 2, 3] } ], "bicycle": { "color": "red", "price": [1, 2, 3] } }, "expensive": 10 }.store.book
console.log(a.map(x=>x.price).reduce((x,y)=>(y.map((i,z)=>x[z]+=y[z]),x)))