Reduce initial value doesn't get evaluated

[Skipperwastaken]

Logic:

{"reduce":[
    {"var":"integers"},
    {"+":[{"var":"current"}, {"var":"accumulator"}]},
    {"var":"start"}
]}

Data:

{
"integers":[1,2,3],
"start": 10
}

I would expect this to return 16, instead it returns null, because the initial value isn't evaluated and can only be a primitive.
Changing the logic to

{"reduce":[
    {"var":"integers"},
    {"+":[{"var":"current"}, {"var":"accumulator"}]},
    10
]}

makes the expression work as expected.

[Tiglat-Pileser]

This is due to how the var-operator works within certain array-functions (see #130 ).

In your particular case there is a workaround, adding the start-variable as the first element of the array to be reduced:
{"reduce":[
{"merge": [{"var": "start"}, {"var":"integers"}]},
{"+":[{"var":"current"}, {"var":"accumulator"}]},
0
]}

[Skipperwastaken]

Thanks for the workaround. I'd like to mention though that there is a difference between this issue and the ones mentioned in #130. As you can see, the var function works correctly as the first parameter of the reduce function.

scopedData = jsonLogic.apply(values[0], data);
scopedLogic = values[1];
initial = typeof values[2] !== "undefined" ? values[2] : null;

This is because in the source code, you can see that the jsonLogicApply function is ran on the first argument, but not on the third one. Changing that line to initial = typeof values[2] !== "undefined" ? jsonLogic.apply(values[2], data) : null; would solve the problem. Which is actually what this PR does, it only needs merging.

[Tiglat-Pileser]

Aye, it is not exactly the same, but the general problem is; External evaluation of "var" only happens for the first argument of map, reduce, filter, etc. and its evaluation is done with restricted scope for all following instances of "var", where actually the restricted scope should only apply to the specific second argument where you want to browse your array or accumulator-object.

[Skipperwastaken]

Again, not quite correct. Evaluation for the third argument doesn't happen at all, not even with a restricted scope and it's not just var, no function works with the third argument, only primitive values.

[Tiglat-Pileser]

I see, I stand corrected then. Thanks for clarifying that to me.

[jwadhams]

Thanks, @ubik2 , I just merged your PR and tagged release 2.0.3 Hopefully it'll be on NPM in a few minutes.

[jwadhams]

Ugh, I think I kind of biffed that release (I don't spend a lot of time publishing to NPM as you might have noticed) so you might want to jump all the way to 2.0.5

[jwadhams]

This is also part of the shared unit tests https://jsonlogic.com/tests.json and in the PHP library as of 1.5.1