JSON Power Query

This is a simple JSON querying mechanism similar to jsonpath. This mechanism allows for ultra-fast queries by "compiling" your queries into evaluated JavaScript.

At the same time, the mechanism uses json-logic-engine to power its filtering, to prevent the unsafe evaluation of any JavaScript code.

$3

Given the following:
``js
const request = {
body: {
name: "John Doe",
age: 35,
friends: [
{
name: "Steve",
age: 23
},
{
name: "Bob",
age: 65
},
{
name: "Erik",
age: 33
}
]
},
params: {
id: 101
}
}
`


Requesting a single property:
`js
const { queryBuilder, objectQueryBuilder } = require('json-query-engine')
const nameGetter = queryBuilder('$.body.name')
console.log(nameGetter(request)) // prints: John Doe
`


Requesting nested properties from an array:
`js
const friendsNames = queryBuilder('$.body.friends.*.name')
console.log(JSON.stringify(friendsNames(request))) // prints: ["Steve", "Bob", "Erik"]
`

Requesting filtered values from an array:
`js
// the filtering uses json-logic-engine, and uses truthiness.
const olderFriendNames = queryBuilder('$.body.friends.*{ ">": [{ "var": "age" }, 30] }.name')
console.log(JSON.stringify(olderFriendNames(request))) // prints: ["Bob", "Erik"]
`

Alternatively, you can use the more normal looking JSONPath Syntax:
`js
const olderFriendNames = queryBuilder('$.body.friends.[?(@.age > 30)].name')
console.log(JSON.stringify(olderFriendNames(request))) // prints: ["Bob", "Erik"]
`


You can also build a function that transforms object shapes into different shapes:
`js
const f = objectQueryBuilder({
name: '$.body.name',
friends: '$.body.friends.*.name',
id: '$.params.id',
meta: {
friendAges: '$.body.friends.*.age'
}
})

const y = f(request)
/* Generates:
* { 
* "name": "John Doe", 
* "friends": [ 
* "Steve", 
* "Bob", 
* "Erik" 
* ], 
* "id": 101, 
* "meta": { 
* "friendAges": [ 
* 23, 
* 65, 
* 33 
* ] 
* } 
* }
*/ 

``