Function aggregateParams

docs/app/js/sanddance-app.js:118122–118134

(_, pulse)

// First collect all unique pivot field values.
// Then generate aggregate fields for each output pivot field.
function aggregateParams(_, pulse) {
    const key = _.field, value = _.value, op = (_.op === "count" ? "__count__" : _.op) || "sum", fields = (0, _vegaUtil.accessorFields)(key).concat((0, _vegaUtil.accessorFields)(value)), keys = pivotKeys(key, _.limit || 0, pulse); // if data stream content changes, pivot fields may change
    // flag parameter modification to ensure re-initialization
    if (pulse.changed()) _.set("__pivot__", null, null, true);
    return {
        key: _.key,
        groupby: _.groupby,
        ops: keys.map(()=>op),
        fields: keys.map((k)=>get(k, key, value, fields)),
        as: keys.map((k)=>k + ""),
        modified: _.modified.bind(_)
    };
} // Generate aggregate field accessor.
// Output NaN for non-existent values; aggregator will ignore!
function get(k, key, value, fields) {
    return (0, _vegaUtil.accessor)((d)=>key(d) === k ? value(d) : NaN, fields, k + "");