René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"`@property` incorrectly excludes array index 0 because javascript treats `0` as false","articleBody":"Consider a sample JSON Document: \n```\n {\n    \"store\": {\n        \"book\": [{\n            \"category\": \"reference\",\n            \"author\": \"Nigel Rees\",\n            \"title\": \"Sayings of the Century\",\n            \"price\": 8.95\n        },\n        {\n            \"category\": \"fiction\",\n            \"author\": \"Evelyn Waugh\",\n            \"title\": \"Sword of Honour\",\n            \"price\": 12.99\n        },\n        {\n            \"category\": \"fiction\",\n            \"author\": \"Herman Melville\",\n            \"title\": \"Moby Dick\",\n            \"isbn\": \"0-553-21311-3\",\n            \"price\": 8.99\n        },\n        {\n            \"category\": \"fiction\",\n            \"author\": \"J. R. R. Tolkien\",\n            \"title\": \"The Lord of the Rings\",\n            \"isbn\": \"0-395-19395-8\",\n            \"price\": 22.99\n        }],\n        \"bicycle\": {\n            \"color\": \"red\",\n            \"price\": 19.95\n        }\n    }\n}\n```\n**Issue:**\nWhen using a filter operation with `@property` , JSONPath Plus incorrectly excludes array elements whose property (array index) is 0, because in JavaScript if(0) means it returns false.\n\nExample JSONPath expression:\n\n``` $.store.bicycle[?(@property)] ```\n\n**Output**\n```\nred,\n19.95\n```\nThis works correctly because the children have string keys (\"color\" , \"price\"), which are truthy. Since each child has a property key , the filter operation for `@property` evaluate to true ,and therefore all child nodes are included.\n\nBut,\n```\n$.store.book[?(@property)]\n```\nHere, book is an array and then the `@property` for the array elements are going to be the array indices.\n\n- For the first element , `@property` is 0 (its array index)\n- For the second element, `@property` is 1  and so on.\n\nBut, here the problem is since for the first element array index is 0 , `@property` = 0, JavaScript evaluates if(0) as false. So, the first book element is incorrectly excluded. Only array elements at index 1,2,3 appear, because their properties are `1, 2, 3` , which are truthy. But the first array element should also be included since it also has a property.\n\n**JSONPath Expression** \n\n```\n$.store.book[?(@property)]\n```\n**Actual Output** : Output lists except the first array element\n```\n        {\n            \"category\": \"fiction\",\n            \"author\": \"Evelyn Waugh\",\n            \"title\": \"Sword of Honour\",\n            \"price\": 12.99\n        },\n        {\n            \"category\": \"fiction\",\n            \"author\": \"Herman Melville\",\n            \"title\": \"Moby Dick\",\n            \"isbn\": \"0-553-21311-3\",\n            \"price\": 8.99\n        },\n        {\n            \"category\": \"fiction\",\n            \"author\": \"J. R. R. Tolkien\",\n            \"title\": \"The Lord of the Rings\",\n            \"isbn\": \"0-395-19395-8\",\n            \"price\": 22.99\n        }\n```\n\n**Expected Output** : Output should list all array elements\n         {\n            \"category\": \"reference\",\n            \"author\": \"Nigel Rees\",\n            \"title\": \"Sayings of the Century\",\n            \"price\": 8.95\n        },\n        {\n            \"category\": \"fiction\",\n            \"author\": \"Evelyn Waugh\",\n            \"title\": \"Sword of Honour\",\n            \"price\": 12.99\n        },\n        {\n            \"category\": \"fiction\",\n            \"author\": \"Herman Melville\",\n            \"title\": \"Moby Dick\",\n            \"isbn\": \"0-553-21311-3\",\n            \"price\": 8.99\n        },\n        {\n            \"category\": \"fiction\",\n            \"author\": \"J. R. R. Tolkien\",\n            \"title\": \"The Lord of the Rings\",\n            \"isbn\": \"0-395-19395-8\",\n            \"price\": 22.99\n        }\n```\n\n\n\nEnvironment\n- JSONPath-Plus version:  jsonpath-plus@10.3.0\n\nDesktop\n - OS: Ubuntu (Linux)\n - Node Version:  v18.13.0\n\n","author":{"url":"https://github.com/Laavanja19","@type":"Person","name":"Laavanja19"},"datePublished":"2025-12-08T07:30:35.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/245/JSONPath/issues/245"}