JSONPath cannot query if condition is a child's property of array

Question

I have a json as below. I want to select list reference of item which has method is "method A". But I cannot query with operator == (with Jayway JSONPath evaluation)

$.items[*].[?(@.methods[*].name == 'method A')].reference

But when I replace operator as contains, the jsonpath works.

$.items[*].[?(@.methods[*].name contains 'method A')].reference

I don't know why operator == does not work. Could anyone help me explain the reason? JSON:

{
    "name": "List codes",
    "items": [
        {            
            "name": "Cash",
            "reference": "CA",
            "methods": [
                {                    
                    "name": "method A",
                    "id": "3543"
                },
                {
                    "name": "method B",
                    "id": "3544"
                }
            ]
        },
        {            
            "name": "Debt",
            "reference": "DE",
            "methods": [
                {                    
                    "name": "method C",
                    "id": "3545"
                },
                {
                    "name": "method B",
                    "id": "3544"
                }
            ]
        },
        {            
            "name": "Property",
            "reference": "PR",
            "methods": [
                {                    
                    "name": "method C",
                    "id": "3545"
                },
                {
                    "name": "method A",
                    "id": "3543"
                }
            ]
        }
    ]
}

Answer 1

@.methods[*].name will yield multiple results resulting into an array. You cannot use == to compare list of values with a string.

if you need to use == operator then you have to use the index along with ||

$.items[?(@.methods[0].name == 'method A' || @.methods[1].name == 'method A')].reference