code: function notifySplices(inst, array, path, splices) {
    let splicesPath = path + '.splices';
    inst.notifyPath(splicesPath, { indexSplices: splices });
    inst.notifyPath(path + '.length', array.length);
    // Null here to allow potentially large splice records to be GC'ed.
    inst.__data[splicesPath] = {indexSplices: null};
  }
docs: data api 
  Sends array splice notifications (`.splices` and `.length`)
  
  Note: this implementation only accepts normalized paths
  
  @param {!PropertyEffectsType} inst Instance to send notifications to
  @param {Array} array The array the mutations occurred on
  @param {string} path The path to the array that was mutated
  @param {Array} splices Array of splice records
  @return {void}
  @private