JS Object Query Syntax

Question

I'm trying to find a way filter js collection with a query syntax similar to SQL.

The only library I found to accomplish this task is json-query.

It works in some cases but it has limitations. It isn't possible to query on different object levels with the same query or query for more than one result.

Here are some examples (Take the datastructure below as reference)

 [{
           "type": "UU",
            "value": "100",
            "tipo": "G",
            "strumento": "P",
            "aspetto": "C",
            "unit": "ml"
        },
        {
            "type": "PS",
            "value": "120/88",
            "rilevamento": "Manuale",
            "lato": "SX",
            "part": "Supina",
            "unit": "mmHg"
        },
        {
            "type": "TP",
            "value": "33.6",
            "tipo": "T",
            "unit": "°C"
        },
        {
            "type": "VO",
            "value": "12",
            "tipo": "VOAL",
            "unit": "ml"
        },
        {
            "type": "RS",
            "value": "60",
            "unit": "atti/min"
        },
        {
            "type": "HH",
            "value": "180",
            "modalita": "R",
            "unit": "cm"
        },
        {
            "type": "AA",
            "value": "50",
            "unit": "cm"
        },
        {
            "type": "PO",
            "value": "70",
            "rilevamento": "Manuale",
            "tipo": "FA",
            "sede": "PC",
            "unit": "bpm"
        }
    ]

type = TP with value > 30

[type=TP & value>30] (works with json-query)

type = TP with value > 30 AND type = UU with value > 90

[type=TP & value>30 & type = UU with value > 90](not working with json-query)

Kamil Folwarczny · Accepted Answer · 2018-10-19 06:25:04Z

2

By brief look on json-query page, I think your second query is wrong. Without * query will return only one record. Your query then doesnt make sense you cant have one item with two different type. I think your query should looks like this:

[* type=TP & value > 30 | type = UU & value > 90]

I can be wrong tho, i have never worked with that library.

Edit for comments

You cant do this with simle query, because every object is tested by your query and simply return bool value if it fits or not. You need to filter your data by first condition and the result filter with second condition.

var tempData = jsonQuery('[* type = TP & value > 30]', {data: data}).value;
var result =   jsonQuery('[* type = UU & value > 90]', {data: tempData }).value;

Edit - Possible solution

If you need to create query beforehand i would consider using array for storing single query and then apply them in sequence. I dont know if are you creating query in JS or on server so i wrote it in JS for code consistency.

var result;
var queryArray;

queryArray.push("[* type = TP & value > 30]");
queryArray.push("[* type = UU & value > 90]");

for (i = 0; i < queryArray.length; i++) {
    result = jsonQuery(queryArray[i], {data: result }).value;
}

edited Oct 19, 2018 at 6:25

answered Oct 18, 2018 at 7:59

Kamil Folwarczny

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6 Comments

Pietro Over a year ago

The query you mention works, but what if you want to return the results only if both exists (TP and UU) with corresponding values?

Kamil Folwarczny Over a year ago

how can you return object where both TP and UU exists when your objects have only one type and one value? Or do you want to return whole list if it contains objects with these values?

Pietro Over a year ago

In your example the result is: [ { type: "TP", value: "33.6", tipo: "T", unit: "°C" }, { type: "VO", value: "12", tipo: "VOAL", unit: "ml" } ]. With the OR condition both they match. I want the same with the AND condition. Of course the query sintax must be different, for example ([type=TP & value > 30] & [type=VO & value > 10]). No results if one of them is not present.

Pietro Over a year ago

"Return whole list if it contains objects", this also could be an acceptable solution.

Pietro Over a year ago

That's is actually something I wanted to avoid. Consider that could be more complex, maybe with 3 different types o more, mixed with AND/OR conditions. I would like to be able to firstly create the query string with some params without writing code. The solution should be: 'select * where Cond1 & Cond2'

|

Dhaval Pankhaniya · Accepted Answer · 2018-10-18 07:15:29Z

1

i think you should use JsLinq

var myList = [
{FirstName:"Chris",LastName:"Pearson"},
{FirstName:"Kate",LastName:"Johnson"},
{FirstName:"Josh",LastName:"Sutherland"},
{FirstName:"John",LastName:"Ronald"},
{FirstName:"Steve",LastName:"Pinkerton"}    ];

var exampleArray = JSLINQ(myList)
.Where(function(item){ return item.FirstName == "Chris"; })
.OrderBy(function(item) { return item.FirstName; })
.Select(function(item){ return item.FirstName; });

answered Oct 18, 2018 at 7:15

Dhaval Pankhaniya

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3 Comments

Pietro Over a year ago

JSLINQ isnt' a query string.

Dhaval Pankhaniya Over a year ago

you want to filter records on query string bases ?

Pietro Over a year ago

Yes, I want to be able to create a query string that I can execute on a data collection. Like: jsonQuery('[type=TP & value>30]', data)

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