Function getUniqueInfo

src/traces/parcats/calc.js:391–437

* Compute unique value information for an array * * IMPORTANT: Note that values are considered unique * if their string representations are unique. * * @param {Array} values * @param {Array|undefined} uniqueValues * Array of expected unique values. The uniqueValues property of the resulting

(values, uniqueValues)

 * @return {UniqueInfo}
 */
function getUniqueInfo(values, uniqueValues) {
    // Initialize uniqueValues if not specified
    if(uniqueValues === undefined || uniqueValues === null) {
        uniqueValues = [];
    } else {
        // Shallow copy so append below doesn't alter input array
        uniqueValues = uniqueValues.map(function(e) {return e;});
    }

    // Initialize Variables
    var uniqueValueCounts = {};
    var uniqueValueInds = {};
    var inds = [];

    // Initialize uniqueValueCounts and
    uniqueValues.forEach(function(uniqueVal, valInd) {
        uniqueValueCounts[uniqueVal] = 0;
        uniqueValueInds[uniqueVal] = valInd;
    });

    // Compute the necessary unique info in a single pass
    for(var i = 0; i < values.length; i++) {
        var item = values[i];
        var itemInd;

        if(uniqueValueCounts[item] === undefined) {
            // This item has a previously unseen value
            uniqueValueCounts[item] = 1;
            itemInd = uniqueValues.push(item) - 1;
            uniqueValueInds[item] = itemInd;
        } else {
            // Increment count for this item
            uniqueValueCounts[item]++;
            itemInd = uniqueValueInds[item];
        }
        inds.push(itemInd);
    }

    // Build UniqueInfo
    var uniqueCounts = uniqueValues.map(function(v) { return uniqueValueCounts[v]; });

    return {
        uniqueValues: uniqueValues,
        uniqueCounts: uniqueCounts,
        inds: inds
    };
}


/**