JSON Logic
Proposal - Arithmetic Operators #21
Replies: 6 comments 20 replies
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Self Happy to try to account for community feedback. |
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+1 from me |
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Should we consider covering test cases for null and other extreme cases [
{
"description": "Addition with null values",
"rule": { "+": [null, 1, null] },
"result": 1,
"data": null
},
{
"description": "Addition with empty string",
"rule": { "+": ["", 1] },
"result": 1,
"data": null
},
{
"description": "Addition with non-numeric strings",
"rule": { "+": ["abc", 1] },
"result": 1,
"data": null
},
{
"description": "Addition with undefined/missing values",
"rule": { "+": [{"var": "missing"}, 1] },
"result": 1,
"data": {}
},
{
"description": "Addition with arrays",
"rule": { "+": [[1,2], 3] },
"result": 3,
"data": null
},
{
"description": "Addition with objects",
"rule": { "+": [{"foo": "bar"}, 1] },
"result": 1,
"data": null
}
] |
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Or introduce an explicit representation of an error, which can be “bubbled up”. |
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@gregsdennis @dslmeinte I might copy this input into this discussion here: https://github.com/orgs/json-logic/discussions/20 We need to decide on whether JSON Logic has "Soft Errors" that emit from operators (NaN or some explicit error representation), or strictly "Hard Errors" that halt AST execution. And how we can check for that in our test spec. I'm open to many options here, but I think we do need to mandate it to be consistent. |
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(I think we'd encounter significant pain if some implementations Hard Errored while others Soft Errored -- what I meant by consistency. So if we defined that coercion of an array is a soft error, I think it should be represented that way across all implementations) |
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In which case a |
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@JTeeuwissen I'm copying this over to the other thread (for errors). 😄 |
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It's my impression that a lot/most of the JSON Logic operators are “implied |
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I agree with this mental model & your assessment it's a bit weird for divide and modulo 😀 (I've personally been calling those operators "variadic") I think it might be good to mention this terminology in the proposals; thank you! For consistency between arithmetic operators, I did decide to include variadic / foldLeft test cases for divide and modulo; even though I anticipate this will be rarely used |
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To be petulantly nerdy here: I think the term “variadic” pertains to functions/operations/operators having a variable (in the sense of: any) number of arguments. The foldLeft semantics are orthogonal to that: you could also say that the function/operation/operator has 1 “listy” (or maybe even
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Oh for sure! there are definitely additional nuances implied by foldLeft: I'll probably incorporate this descriptor in. (However, for the comparison operators which will likely be next, those will probably be best described as variadic -- should we decide to upgrade them) |
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Could you please highlight any differences between this proposal and what's currently defined in JSON Logic? The proposal makes sense, so I'll give it a |
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Keeping the spec and test cases agnostic to precision was the main intention. |
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Only two small changes from the main implementation,
I've basically carried forward all of the tests from the original and added more cases around each. |
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To help communicate expectations, most of the incoming proposals will just be codifying test cases for existing operators and better defining edge-case behaviors and trying to improve consistency in between families of operators. |
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Perhaps I've missed it, but I feel like type coercion should be a discussion on its own. Especially when considering future equality operators. I personally would like to avoid coercion as much as possible, since I feel like their use case is rare, easily solved with explicit conversions and that implicit coercion is error prone for users. Additionally, when defining string parsing (preferably explicitly), I think it would be better to accept any valid json number as string (e.g. including scientific notation). |
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Ah! The scientific notation! Good catch, I can revise the proposal for that immediately. Part of the issue with avoiding coercion is that the mainline tests.json include tests that use both strings & numbers, and they implicitly coerce for the arithmetic and comparison operators. (Except the strict ones) As much as possible, I'd like to be backwards compatible with existing logic & implementations. Personally, I don't love implicit conversions, but I feel it's important to not break compatibility. I don't think any other operators should feature coercion though. |
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Hey -- while I can come off pretty aggressive about the backwards compat thing, I promise I'm open to exploring options 😅. Like: If the community felt But for the purposes of substr and other operators which can receive numeric arguments, I don't intend to mandate implicit coercion. Just passively noting the following, "as defined"
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@json-logic/tc Calling for a revote, I've amended this to include error boundaries to answer https://github.com/orgs/json-logic/discussions/21#discussioncomment-11871756 I'm giving this a self +1. (For non-TC members, I'm going to assume the error boundaries did not change the vote unless otherwise announced... based on convos I've had) Current Votes
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Background
JSON Logic includes various arithmetic operators, namely:
+,-,/,*and%.This proposal seeks to evaluate these operators and tests to recognize them in JSON Logic Core.
Proposal
As decided in a previous proposal, these operators are being defined with agnostic precision and from a pure mathematical perspective.
These operators are expected to coerce booleans and strings into numeric values.
+-*/%Default unary behavior is just to return the argument coerced into a number.
The coercion behavior being defined at this time is the following:
stringis parsed as a JSON Number (e.g.1,1.23,1e5should be valid). Empty string becomes 0.truebecomes 1falsebecomes 0nullbecomes 0There are two changes from mainline json-logic:
/and%follow the default unary behavior, injson-logic-js{ "/": [1] }returnedNaN, I think it can make sense for them to return the first operand, especially since*already worked this way./and%also support variadic functionality, for consistency.For the purposes of tests, I am not distinguishing between
-0and0to try to remain precision / implementation agnostic.-0does not seem purely mathematical.These operators are variadic, with an implied foldLeft behavior.
{ "+": [1, 2, 3] }is1 + 2 + 3.Controversial: I am marking the tests that use fractional numbers with a
"decimal": trueproperty. The original JSON Logictests.jsondid have a division test that resulted in a fractional number. Normally I'd omit it, but I'll carry the test for it forward as it is relatively precision agnostic, and we are aiming to honor the originaltests.json.If someone chose to implement an integer-based version of JSON Logic Core, they can decide how they want to handle those tests (like truncating).
For our purposes, it changes nothing; it's just an annotation.
Tests
+Operator[ "# Collection of Plus Operator Tests", { "description": "Addition", "rule": { "+": [1, 2] }, "result": 3, "data": null }, { "description": "Addition (2)", "rule": { "+": [5, 12] }, "result": 17, "data": null }, { "description": "Addition with Multiple Operands", "rule": { "+": [1, 2, 3, 4] }, "result": 10, "data": null }, { "description": "Addition with Negative Numbers", "rule": { "+": [-1, 0, 5] }, "result": 4, "data": null }, { "description": "Addition with Strings", "rule": { "+": ["1", "2", "3"] }, "result": 6, "data": null }, { "description": "Addition with Booleans", "rule": { "+": [true, false, true] }, "result": 2, "data": null }, { "description": "Addition with Multiple Value Types", "rule": { "+": [1, "2", 3, "4", "", true, false, null] }, "result": 11, "data": null }, { "description": "Plus Operator with Single Operand (Number)", "rule": { "+": [1] }, "result": 1, "data": null }, { "description": "Plus Operator with Single Operand (Negative Number)", "rule": { "+": [-1] }, "result": -1, "data": null }, { "description": "Plus Operator with Single Operand, Direct (Number)", "rule": { "+": 1 }, "result": 1, "data": null }, { "description": "Plus Operator with Single Operand, Direct (0)", "rule": { "+": 0 }, "result": 0, "data": null }, { "description": "Plus Operator with Single Operand (String)", "rule": { "+": ["1"] }, "result": 1, "data": null }, { "description": "Plus Operator with Single Operand, Direct (Negative Number String)", "rule": { "+": "-1" }, "result": -1, "data": null }, { "description": "Plus Operator with Single Operand, Direct (String Decimal)", "rule": { "+": "1.5" }, "result": 1.5, "data": null, "decimal": true }, { "description": "Plus Operator with Single Operand, Direct (String Negative Decimal)", "rule": { "+": "-1.5" }, "result": -1.5, "data": null, "decimal": true }, { "description": "Plus Operator with Single Operand, Direct (String 0.5)", "rule": { "+": "0.5" }, "result": 0.5, "data": null, "decimal": true }, { "description": "Plus Operator with Single Operand, Direct (String 1e2)", "rule": { "+": "1e2" }, "result": 100, "data": null }, { "description": "Plus Operator with Single Operand, Direct (String 0)", "rule": { "+": "0" }, "result": 0, "data": null }, { "description": "Plus Operator with Single Operand, Direct (true)", "rule": { "+": true }, "result": 1, "data": null }, { "description": "Plus Operator with Single Operand, Direct (false)", "rule": { "+": false }, "result": 0, "data": null }, { "description": "Plus Operator with Single Operand, Direct (Empty String)", "rule": { "+": "" }, "result": 0, "data": null }, { "description": "Plus Operator with a Single Operand, Direct (null)", "rule": { "+": null }, "result": 0, "data": null }, { "description": "Addition with val", "rule": { "+": [{ "val": "x" }, { "val": "y" }] }, "result": 3, "data": { "x": 1, "y": 2 } }, { "description": "Addition with string produces NaN", "rule": { "+": ["Hey", 1] }, "error": { "type": "NaN" }, "data": null }, { "description": "Addition with Array produces NaN", "rule": { "+": [[1], 1] }, "error": { "type": "NaN" }, "data": null }, { "description": "Addition with Array from context produces NaN", "rule": { "+": [{ "val": "x" }, 1] }, "error": { "type": "NaN" }, "data": { "x": [1] } }, { "description": "Addition with Object produces NaN", "rule": { "+": [{ "val": "x" }, 1] }, "error": { "type": "NaN" }, "data": { "x": {} } }, { "description": "Plus Operator with Single Operand, Invalid String Produces NaN", "rule": { "+": "Hello" }, "error": { "type": "NaN" }, "data": null }, { "description": "Plus Operator with Single Operand, Array Input Produces NaN", "rule": { "+": [[1]] }, "error": { "type": "NaN" }, "data": null }, { "description": "Plus Operator with Single Operand, Object Input Produces NaN", "rule": { "+": [{}] }, "error": { "type": "NaN" }, "data": null }, { "description": "Plus Operator with Single Operand, Direct Object Input Produces NaN", "rule": { "+": {} }, "error": { "type": "NaN" }, "data": null } ]-Operator[ "# Collection of Minus Operator Tests", { "description": "Subtraction", "rule": { "-": [1, 2] }, "result": -1, "data": null }, { "description": "Subtraction (2)", "rule": { "-": [5, 12] }, "result": -7, "data": null }, { "description": "Subtraction with Multiple Operands", "rule": { "-": [1, 2, 3, 4] }, "result": -8, "data": null }, { "description": "Subtraction with Negative Numbers", "rule": { "-": [-1, 0, 5] }, "result": -6, "data": null }, { "description": "Subtraction with Strings", "rule": { "-": ["1", "2", "3"] }, "result": -4, "data": null }, { "description": "Subtraction with Booleans", "rule": { "-": [true, false, true] }, "result": 0, "data": null }, { "description": "Subtraction with Multiple Value Types", "rule": { "-": [1, "2", 3, "4", "", true, false, null] }, "result": -9, "data": null }, { "description": "Minus Operator with Single Operand (Number)", "rule": { "-": [1] }, "result": -1, "data": null }, { "description": "Minus Operator with Single Operand (Negative Number)", "rule": { "-": [-1] }, "result": 1, "data": null }, { "description": "Minus Operator with Single Operand, Direct (Number)", "rule": { "-": 1 }, "result": -1, "data": null }, { "description": "Minus Operator with Single Operand, Direct (0)", "rule": { "-": 0 }, "result": 0, "data": null }, { "description": "Minus Operator with Single Operand (String)", "rule": { "-": ["1"] }, "result": -1, "data": null }, { "description": "Minus Operator with Single Operand, Direct (Negative Number String)", "rule": { "-": "-1" }, "result": 1, "data": null }, { "description": "Minus Operator with Single Operand, Direct (String 0)", "rule": { "-": "0" }, "result": 0, "data": null }, { "description": "Minus Operator with Single Operand, Direct (true)", "rule": { "-": true }, "result": -1, "data": null }, { "description": "Minus Operator with Single Operand, Direct (false)", "rule": { "-": false }, "result": 0, "data": null }, { "description": "Minus Operator with Single Operand, Direct (Empty String)", "rule": { "-": "" }, "result": 0, "data": null }, { "description": "Minus Operator with a Single Operand, Direct (null)", "rule": { "-": null }, "result": 0, "data": null }, { "description": "Subtraction with val", "rule": { "-": [{ "val": "x" }, { "val": "y" }] }, "data": { "x": 1, "y": 2 }, "result": -1 }, { "description": "Subtraction with string produces NaN", "rule": { "-": ["Hey", 1] }, "error": { "type": "NaN" }, "data": null }, { "description": "Subtraction with Array produces NaN", "rule": { "-": [[1], 1] }, "error": { "type": "NaN" }, "data": null } ]*Operator[ "# Collection of Multiply Operator Tests", { "description": "Multiply", "rule": { "*": [3, 2] }, "result": 6, "data": null }, { "description": "Multiply with Multiple Operands", "rule": { "*": [5, 10, 2] }, "result": 100, "data": null }, { "description": "Multiply with Multiple Operands (2)", "rule": { "*": [2, 2, 2] }, "result": 8, "data": null }, { "description": "Multiply with Negative Numbers", "rule": { "*": [-1, 2, 5] }, "result": -10, "data": null }, { "description": "Multiply with Strings", "rule": { "*": ["1", "2", "3"] }, "result": 6, "data": null }, { "description": "Multiply with Booleans", "rule": { "*": [true, false, true] }, "result": 0, "data": null }, { "description": "Multiply with Multiple Value Types", "rule": { "*": [1, "2", 3, "4", true] }, "result": 24, "data": null }, { "description": "Multiply with Multiple Value Types (2)", "rule": { "*": [1, "1"] }, "result": 1, "data": null }, { "description": "Multiply with Multiple Value Types (3)", "rule": { "*": ["1", null] }, "result": 0, "data": null }, { "description": "Multiply with Single Operand (Number)", "rule": { "*": [1] }, "result": 1, "data": null }, { "description": "Multiply with Single Operand, Direct (Number)", "rule": { "*": 1 }, "result": 1, "data": null }, { "description": "Multiply with Single Operand, Direct (0)", "rule": { "*": 0 }, "result": 0, "data": null }, { "description": "Multiply Operator with Single Operand (Number)", "rule": { "*": [1] }, "result": 1, "data": null }, { "description": "Multiply Operator with Single Operand (Negative Number)", "rule": { "*": [-1] }, "result": -1, "data": null }, { "description": "Multiply Operator with Single Operand, Direct (Number)", "rule": { "*": 1 }, "result": 1, "data": null }, { "description": "Multiply Operator with Single Operand, Direct (0)", "rule": { "*": 0 }, "result": 0, "data": null }, { "description": "Multiply Operator with Single Operand (String)", "rule": { "*": ["1"] }, "result": 1, "data": null }, { "description": "Multiply Operator with Single Operand, Direct (Negative Number String)", "rule": { "*": "-1" }, "result": -1, "data": null }, { "description": "Multiply Operator with Single Operand, Direct (String 0)", "rule": { "*": "0" }, "result": 0, "data": null }, { "description": "Multiply Operator with Single Operand, Direct (true)", "rule": { "*": true }, "result": 1, "data": null }, { "description": "Multiply Operator with Single Operand, Direct (false)", "rule": { "*": false }, "result": 0, "data": null }, { "description": "Multiply Operator with Single Operand, Direct (Empty String)", "rule": { "*": "" }, "result": 0, "data": null }, { "description": "Multiply Operator with a Single Operand, Direct (null)", "rule": { "*": null }, "result": 0, "data": null }, { "description": "Multiply with val", "rule": { "*": [{ "val": "x" }, { "val": "y" }] }, "data": { "x": 8, "y": 2 }, "result": 16 }, { "description": "Multiply with string produces NaN", "rule": { "*": ["Hey", 1] }, "error": { "type": "NaN" }, "data": null }, { "description": "Multiply with a single string produces NaN", "rule": { "*": ["Hey"] }, "error": { "type": "NaN" }, "data": null }, { "description": "Multiply with Array produces NaN", "rule": { "*": [[1], 1] }, "error": { "type": "NaN" }, "data": null } ]/Operator[ "# Collection of Divide Operator Tests", { "description": "Divide", "rule": { "/": [4, 2] }, "result": 2, "data": null }, { "description": "Divide to Decimal", "rule": { "/": [2, 4] }, "result": 0.5, "data": null, "decimal": true }, { "description": "Divide with Multiple Operands", "rule": { "/": [8, 2, 2] }, "result": 2, "data": null }, { "description": "Divide with Multiple Operands (2)", "rule": { "/": [2, 2, 1] }, "result": 1, "data": null }, { "description": "Divide with Negative Numbers", "rule": { "/": [-1, 2] }, "result": -0.5, "data": null, "decimal": true }, { "description": "Divide with Strings", "rule": { "/": ["8", "2", "2"] }, "result": 2, "data": null }, { "description": "Divide with Booleans", "rule": { "/": [false, true] }, "result": 0, "data": null }, { "description": "Divide with Multiple Value Types", "rule": { "/": ["8", true, 2] }, "result": 4, "data": null }, { "description": "Divide with Multiple Value Types (2)", "rule": { "/": ["1", 1] }, "result": 1, "data": null }, { "description": "Divide with Single Operand (Number)", "rule": { "/": [1] }, "result": 1, "data": null }, { "description": "Divide with Single Operand, Direct (Number)", "rule": { "/": 1 }, "result": 1, "data": null }, { "description": "Divide with Single Operand, Direct (0)", "rule": { "/": 0 }, "result": 0, "data": null }, { "description": "Divide Operator with Single Operand (Number)", "rule": { "/": [1] }, "result": 1, "data": null }, { "description": "Divide Operator with Single Operand (Negative Number)", "rule": { "/": [-1] }, "result": -1, "data": null }, { "description": "Divide Operator with Single Operand, Direct (Number)", "rule": { "/": 1 }, "result": 1, "data": null }, { "description": "Divide Operator with Single Operand, Direct (0)", "rule": { "/": 0 }, "result": 0, "data": null }, { "description": "Divide Operator with Single Operand (String)", "rule": { "/": ["1"] }, "result": 1, "data": null }, { "description": "Divide Operator with Single Operand, Direct (Negative Number String)", "rule": { "/": "-1" }, "result": -1, "data": null }, { "description": "Divide Operator with Single Operand, Direct (String 0)", "rule": { "/": "0" }, "result": 0, "data": null }, { "description": "Divide Operator with Single Operand, Direct (true)", "rule": { "/": true }, "result": 1, "data": null }, { "description": "Divide Operator with Single Operand, Direct (false)", "rule": { "/": false }, "result": 0, "data": null }, { "description": "Divide Operator with Single Operand, Direct (Empty String)", "rule": { "/": "" }, "result": 0, "data": null }, { "description": "Divide Operator with a Single Operand, Direct (null)", "rule": { "/": null }, "result": 0, "data": null }, { "description": "Divide with val", "rule": { "/": [{ "val": "x" }, { "val": "y" }] }, "data": { "x": 8, "y": 2 }, "result": 4 }, { "description": "Divide by Zero", "rule": { "/": [0, 0] }, "error": { "type": "NaN" }, "data": null }, { "description": "Divide with String produces NaN", "rule": { "/": [1, "a"] }, "error": { "type": "NaN" }, "data": null }, { "description": "Divide with Array produces NaN", "rule": { "/": [1, [1]] }, "error": { "type": "NaN" }, "data": null }, { "description": "Any division by zero should return NaN", "rule": { "/": [1, 0] }, "error": { "type": "NaN" }, "data": null }, { "description": "Any division by zero should return NaN (2)", "rule": { "/": [8, 2, 0] }, "error": { "type": "NaN" }, "data": null } ]%Operator[ "# Collection of Modulo Operator Tests", { "description": "Modulo", "rule": { "%": [4, 2] }, "result": 0, "data": null }, { "description": "Modulo (2)", "rule": { "%": [2, 2] }, "result": 0, "data": null }, { "description": "Modulo (3)", "rule": { "%": [3, 2] }, "result": 1, "data": null }, { "description": "Modulo with a Decimal Operand", "rule": { "%": [1, 0.5] }, "result": 0, "data": null, "decimal": true }, { "description": "Modulo with Multiple Operands", "rule": { "%": [8, 6, 3] }, "result": 2, "data": null }, { "description": "Modulo with Multiple Operands (2)", "rule": { "%": [2, 2, 1] }, "result": 0, "data": null }, { "description": "Modulo with Negative Numbers", "rule": { "%": [-1, 2] }, "result": -1, "data": null }, { "description": "Modulo with Strings", "rule": { "%": ["8", "2"] }, "result": 0, "data": null }, { "description": "Modulo with Booleans", "rule": { "%": [false, true] }, "result": 0, "data": null }, { "description": "Modulo with Multiple Value Types", "rule": { "%": ["8", 3, true] }, "result": 0, "data": null }, { "description": "Modulo with Multiple Value Types (2)", "rule": { "%": ["1", 1] }, "result": 0, "data": null }, { "description": "Modulo with Single Operand (Number)", "rule": { "%": [1] }, "result": 1, "data": null }, { "description": "Modulo with Single Operand, Direct (Number)", "rule": { "%": 1 }, "result": 1, "data": null }, { "description": "Modulo with Single Operand, Direct (0)", "rule": { "%": 0 }, "result": 0, "data": null }, { "description": "Modulo Operator with Single Operand (Number)", "rule": { "%": [1] }, "result": 1, "data": null }, { "description": "Modulo Operator with Single Operand (Negative Number)", "rule": { "%": [-1] }, "result": -1, "data": null }, { "description": "Modulo Operator with Single Operand, Direct (Number)", "rule": { "%": 1 }, "result": 1, "data": null }, { "description": "Modulo Operator with Single Operand, Direct (0)", "rule": { "%": 0 }, "result": 0, "data": null }, { "description": "Modulo Operator with Single Operand (String)", "rule": { "%": ["1"] }, "result": 1, "data": null }, { "description": "Modulo Operator with Single Operand, Direct (Negative Number String)", "rule": { "%": "-1" }, "result": -1, "data": null }, { "description": "Modulo Operator with Single Operand, Direct (String 0)", "rule": { "%": "0" }, "result": 0, "data": null }, { "description": "Modulo Operator with Single Operand, Direct (true)", "rule": { "%": true }, "result": 1, "data": null }, { "description": "Modulo Operator with Single Operand, Direct (false)", "rule": { "%": false }, "result": 0, "data": null }, { "description": "Modulo Operator with Single Operand, Direct (Empty String)", "rule": { "%": "" }, "result": 0, "data": null }, { "description": "Modulo Operator with a Single Operand, Direct (null)", "rule": { "%": null }, "result": 0, "data": null }, { "description": "Modulo with val", "rule": { "%": [{ "val": "x" }, { "val": "y" }] }, "data": { "x": 11, "y": 6 }, "result": 5 }, { "description": "Modulo with string produces NaN", "rule": { "%": ["Hey", 1] }, "error": { "type": "NaN" }, "data": null }, { "description": "Modulo with array produces NaN", "rule": { "%": [[1], 1] }, "error": { "type": "NaN" }, "data": null } ]Beta Was this translation helpful? 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