d3plus-common/es/src/merge.js

import { merge, sum } from "d3-array";
import { keys } from "d3-collection";
/**
    @function merge
    @desc Combines an Array of Objects together and returns a new Object.
    @param {Array} objects The Array of objects to be merged together.
    @param {Object} aggs An object containing specific aggregation methods (functions) for each key type. By default, numbers are summed and strings are returned as an array of unique values.
    @example <caption>this</caption>
merge([
  {id: "foo", group: "A", value: 10, links: [1, 2]},
  {id: "bar", group: "A", value: 20, links: [1, 3]}
]);
    @example <caption>returns this</caption>
{id: ["bar", "foo"], group: "A", value: 30, links: [1, 2, 3]}
*/

function objectMerge(objects) {
  var aggs = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
  var availableKeys = new Set(merge(objects.map(function (o) {
    return keys(o);
  }))),
      newObject = {};
  availableKeys.forEach(function (k) {
    var values = objects.map(function (o) {
      return o[k];
    });
    var value;
    if (aggs[k]) value = aggs[k](values);else {
      var types = values.map(function (v) {
        return v || v === false ? v.constructor : v;
      }).filter(function (v) {
        return v !== void 0;
      });
      if (!types.length) value = undefined;else if (types.indexOf(Array) >= 0) {
        value = merge(values.map(function (v) {
          return v instanceof Array ? v : [v];
        }));
        value = Array.from(new Set(value));
        if (value.length === 1) value = value[0];
      } else if (types.indexOf(String) >= 0) {
        value = Array.from(new Set(values));
        if (value.length === 1) value = value[0];
      } else if (types.indexOf(Number) >= 0) value = sum(values);else if (types.indexOf(Object) >= 0) value = objectMerge(values.filter(function (v) {
        return v;
      }));else {
        value = Array.from(new Set(values.filter(function (v) {
          return v !== void 0;
        })));
        if (value.length === 1) value = value[0];
      }
    }
    newObject[k] = value;
  });
  return newObject;
}

export default objectMerge;