substr.json

[
    "Basic Substring",
    {
        "description": "Substr from start index",
        "rule": { "substr": ["jsonlogic", 4] },
        "data": null,
        "result": "logic"
    },
    {
        "description": "Substr with negative start index",
        "rule": { "substr": ["jsonlogic", -5] },
        "data": null,
        "result": "logic"
    },
    "Start and Length",
    {
        "description": "Substr with start and positive length",
        "rule": { "substr": ["jsonlogic", 0, 1] },
        "data": null,
        "result": "j"
    },
    {
        "description": "Substr with negative start and positive length",
        "rule": { "substr": ["jsonlogic", -1, 1] },
        "data": null,
        "result": "c"
    },
    {
        "description": "Substr with start and length",
        "rule": { "substr": ["jsonlogic", 4, 5] },
        "data": null,
        "result": "logic"
    },
    {
        "description": "Substr with negative start and length",
        "rule": { "substr": ["jsonlogic", -5, 5] },
        "data": null,
        "result": "logic"
    },
    "Negative Length",
    {
        "description": "Substr with negative length from end",
        "rule": { "substr": ["jsonlogic", -5, -2] },
        "data": null,
        "result": "log"
    },
    {
        "description": "Substr with positive start and negative length",
        "rule": { "substr": ["jsonlogic", 1, -5] },
        "data": null,
        "result": "son"
    },
    "Edge Cases",
    {
        "description": "Substr with empty string",
        "rule": { "substr": ["", 0, 1] },
        "data": null,
        "result": ""
    },
    {
        "description": "Substr with start beyond string length",
        "rule": { "substr": ["test", 10, 1] },
        "data": null,
        "result": ""
    },
    {
        "description": "Substr with negative start beyond string length",
        "rule": { "substr": ["test", -10, 1] },
        "data": null,
        "result": "t"
    },
    {
        "description": "Substr with non-string input returns empty",
        "rule": { "substr": [42, 0, 1] },
        "data": null,
        "result": "4"
    }
]