const mongoose = require('mongoose'); const Schema = mongoose.Schema; mongoose.Promise = global.Promise; mongoose.level = "F"; // Resolving error Unknown modifier: $pushAll mongoose.plugin(schema => { schema.options.usePushEach = true }); const CategorySchema = new Schema({ name: { type: String, unique: true, index: true, lowercase: true } }); module.exports.getAllCategories = function (callback) { Category.find(callback) } module.exports.getCategoryById = function (id, callback) { Category.findById(id, callback); } module.exports = mongoose.model('Category', CategorySchema);