Chad Johnson Chad Johnson - 1 month ago 7
Javascript Question

How can I create all combinations of this object's keys/values in JavaScript?

I have the following JavaScript object structure:

var options = {
optionOne: [true, false],
optionTwo: [true, false],
optionThree: [
null,
{property1: 9, property2: 7},
{property1: 4, property2: 12},
{property1: 16, property2: 14}
]
};


Please note that the number of key/pairs in this object will differ. So there might actually be
optionFour
,
optionFive
, etc., and each option can have any number or type of values for its array.

I need to iterate through this object and create an array containing objects of all possible option combinations:

[
{optionOne: true, optionTwo, true, optionThree: null},
{optionOne: false, optionTwo, true, optionThree: null},
{optionOne: true, optionTwo, false, optionThree: null},
{optionOne: false, optionTwo, false, optionThree: null},
{optionOne: true, optionTwo, true, optionThree: {property1: 9, property2: 7}},
{optionOne: false, optionTwo, true, optionThree: {property1: 9, property2: 7}},
{optionOne: true, optionTwo, false, optionThree: {property1: 9, property2: 7}},
{optionOne: false, optionTwo, false, optionThree: {property1: 9, property2: 7}},
{optionOne: true, optionTwo, true, optionThree: {property1: 4, property2: 12}},
{optionOne: false, optionTwo, true, optionThree: {property1: 4, property2: 12}},
{optionOne: true, optionTwo, false, optionThree: {property1: 4, property2: 12}},
{optionOne: false, optionTwo, false, optionThree: {property1: 4, property2: 12}},
{optionOne: true, optionTwo, true, optionThree: {property1: 16, property2: 14}},
{optionOne: false, optionTwo, true, optionThree: {property1: 16, property2: 14}},
{optionOne: true, optionTwo, false, optionThree: {property1: 16, property2: 14}},
{optionOne: false, optionTwo, false, optionThree: {property1: 16, property2: 14}}
]


I'm struggling on how to accomplish this but am fairly confident the answer lies in recursion.

Can the algorithm gods help me?

Answer
function getCombinations(options, optionIndex, results, current) {
    var allKeys = Object.keys(options);
    var optionKey = allKeys[optionIndex];

    var vals = options[optionKey];

    for (var i = 0; i < vals.length; i++) {
        current[optionKey] = vals[i];

        if (optionIndex + 1 < allKeys.length) {
            getCombinations(options, optionIndex + 1, results, current);
        } else {
            // The easiest way to clone an object.
            var res = JSON.parse(JSON.stringify(current));
            results.push(res);
        }
    }

    return results;
}

Use it like this:

var results = getCombinations(options, 0, [], {});

Here's a working JSFiddle example.

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