Function mergeWithSources

src/functional/merge.js:31–75

(collection, sources, merger)

}

export function mergeWithSources(collection, sources, merger) {
  if (!isDataStructure(collection)) {
    throw new TypeError(
      'Cannot merge into non-data-structure value: ' + collection
    );
  }
  if (isImmutable(collection)) {
    return typeof merger === 'function' && collection.mergeWith
      ? collection.mergeWith(merger, ...sources)
      : collection.merge
        ? collection.merge(...sources)
        : collection.concat(...sources);
  }
  const isArray = Array.isArray(collection);
  let merged = collection;
  const Collection = isArray ? IndexedCollection : KeyedCollection;
  const mergeItem = isArray
    ? (value) => {
        // Copy on write
        if (merged === collection) {
          merged = shallowCopy(merged);
        }
        merged.push(value);
      }
    : (value, key) => {
        if (isProtoKey(key)) {
          return;
        }

        const hasVal = hasOwnProperty.call(merged, key);
        const nextVal =
          hasVal && merger ? merger(merged[key], value, key) : value;
        if (!hasVal || nextVal !== merged[key]) {
          // Copy on write
          if (merged === collection) {
            merged = shallowCopy(merged);
          }
          merged[key] = nextVal;
        }
      };
  for (let i = 0; i < sources.length; i++) {
    Collection(sources[i]).forEach(mergeItem);
  }
  return merged;
}

function deepMergerWith(merger) {
  function deepMerger(oldValue, newValue, key) {