some progress

node_modules/mongoose/lib/helpers/model/applyDefaultsToPOJO.js

@@ -0,0 +1,52 @@
+'use strict';
+
+module.exports = function applyDefaultsToPOJO(doc, schema) {
+  const paths = Object.keys(schema.paths);
+  const plen = paths.length;
+
+  for (let i = 0; i < plen; ++i) {
+    let curPath = '';
+    const p = paths[i];
+
+    const type = schema.paths[p];
+    const path = type.splitPath();
+    const len = path.length;
+    let doc_ = doc;
+    for (let j = 0; j < len; ++j) {
+      if (doc_ == null) {
+        break;
+      }
+
+      const piece = path[j];
+      curPath += (!curPath.length ? '' : '.') + piece;
+
+      if (j === len - 1) {
+        if (typeof doc_[piece] !== 'undefined') {
+          if (type.$isSingleNested) {
+            applyDefaultsToPOJO(doc_[piece], type.caster.schema);
+          } else if (type.$isMongooseDocumentArray && Array.isArray(doc_[piece])) {
+            doc_[piece].forEach(el => applyDefaultsToPOJO(el, type.schema));
+          }
+
+          break;
+        }
+
+        const def = type.getDefault(doc, false, { skipCast: true });
+        if (typeof def !== 'undefined') {
+          doc_[piece] = def;
+
+          if (type.$isSingleNested) {
+            applyDefaultsToPOJO(def, type.caster.schema);
+          } else if (type.$isMongooseDocumentArray && Array.isArray(def)) {
+            def.forEach(el => applyDefaultsToPOJO(el, type.schema));
+          }
+        }
+      } else {
+        if (doc_[piece] == null) {
+          doc_[piece] = {};
+        }
+        doc_ = doc_[piece];
+      }
+    }
+  }
+};

node_modules/mongoose/lib/helpers/model/applyHooks.js

@@ -0,0 +1,149 @@
+'use strict';
+
+const symbols = require('../../schema/symbols');
+const promiseOrCallback = require('../promiseOrCallback');
+
+/*!
+ * ignore
+ */
+
+module.exports = applyHooks;
+
+/*!
+ * ignore
+ */
+
+applyHooks.middlewareFunctions = [
+  'deleteOne',
+  'save',
+  'validate',
+  'remove',
+  'updateOne',
+  'init'
+];
+
+/*!
+ * ignore
+ */
+
+const alreadyHookedFunctions = new Set(applyHooks.middlewareFunctions.flatMap(fn => ([fn, `$__${fn}`])));
+
+/**
+ * Register hooks for this model
+ *
+ * @param {Model} model
+ * @param {Schema} schema
+ * @param {Object} options
+ * @api private
+ */
+
+function applyHooks(model, schema, options) {
+  options = options || {};
+
+  const kareemOptions = {
+    useErrorHandlers: true,
+    numCallbackParams: 1,
+    nullResultByDefault: true,
+    contextParameter: true
+  };
+  const objToDecorate = options.decorateDoc ? model : model.prototype;
+
+  model.$appliedHooks = true;
+  for (const key of Object.keys(schema.paths)) {
+    const type = schema.paths[key];
+    let childModel = null;
+    if (type.$isSingleNested) {
+      childModel = type.caster;
+    } else if (type.$isMongooseDocumentArray) {
+      childModel = type.Constructor;
+    } else {
+      continue;
+    }
+
+    if (childModel.$appliedHooks) {
+      continue;
+    }
+
+    applyHooks(childModel, type.schema, options);
+    if (childModel.discriminators != null) {
+      const keys = Object.keys(childModel.discriminators);
+      for (const key of keys) {
+        applyHooks(childModel.discriminators[key],
+          childModel.discriminators[key].schema, options);
+      }
+    }
+  }
+
+  // Built-in hooks rely on hooking internal functions in order to support
+  // promises and make it so that `doc.save.toString()` provides meaningful
+  // information.
+
+  const middleware = schema.s.hooks.
+    filter(hook => {
+      if (hook.name === 'updateOne' || hook.name === 'deleteOne') {
+        return !!hook['document'];
+      }
+      if (hook.name === 'remove' || hook.name === 'init') {
+        return hook['document'] == null || !!hook['document'];
+      }
+      if (hook.query != null || hook.document != null) {
+        return hook.document !== false;
+      }
+      return true;
+    }).
+    filter(hook => {
+      // If user has overwritten the method, don't apply built-in middleware
+      if (schema.methods[hook.name]) {
+        return !hook.fn[symbols.builtInMiddleware];
+      }
+
+      return true;
+    });
+
+  model._middleware = middleware;
+
+  objToDecorate.$__originalValidate = objToDecorate.$__originalValidate || objToDecorate.$__validate;
+
+  for (const method of ['save', 'validate', 'remove', 'deleteOne']) {
+    const toWrap = method === 'validate' ? '$__originalValidate' : `$__${method}`;
+    const wrapped = middleware.
+      createWrapper(method, objToDecorate[toWrap], null, kareemOptions);
+    objToDecorate[`$__${method}`] = wrapped;
+  }
+  objToDecorate.$__init = middleware.
+    createWrapperSync('init', objToDecorate.$__init, null, kareemOptions);
+
+  // Support hooks for custom methods
+  const customMethods = Object.keys(schema.methods);
+  const customMethodOptions = Object.assign({}, kareemOptions, {
+    // Only use `checkForPromise` for custom methods, because mongoose
+    // query thunks are not as consistent as I would like about returning
+    // a nullish value rather than the query. If a query thunk returns
+    // a query, `checkForPromise` causes infinite recursion
+    checkForPromise: true
+  });
+  for (const method of customMethods) {
+    if (alreadyHookedFunctions.has(method)) {
+      continue;
+    }
+    if (!middleware.hasHooks(method)) {
+      // Don't wrap if there are no hooks for the custom method to avoid
+      // surprises. Also, `createWrapper()` enforces consistent async,
+      // so wrapping a sync method would break it.
+      continue;
+    }
+    const originalMethod = objToDecorate[method];
+    objToDecorate[method] = function() {
+      const args = Array.prototype.slice.call(arguments);
+      const cb = args.slice(-1).pop();
+      const argsWithoutCallback = typeof cb === 'function' ?
+        args.slice(0, args.length - 1) : args;
+      return promiseOrCallback(cb, callback => {
+        return this[`$__${method}`].apply(this,
+          argsWithoutCallback.concat([callback]));
+      }, model.events);
+    };
+    objToDecorate[`$__${method}`] = middleware.
+      createWrapper(method, originalMethod, null, customMethodOptions);
+  }
+}

node_modules/mongoose/lib/helpers/model/applyMethods.js

@@ -0,0 +1,70 @@
+'use strict';
+
+const get = require('../get');
+const utils = require('../../utils');
+
+/**
+ * Register methods for this model
+ *
+ * @param {Model} model
+ * @param {Schema} schema
+ * @api private
+ */
+
+module.exports = function applyMethods(model, schema) {
+  const Model = require('../../model');
+
+  function apply(method, schema) {
+    Object.defineProperty(model.prototype, method, {
+      get: function() {
+        const h = {};
+        for (const k in schema.methods[method]) {
+          h[k] = schema.methods[method][k].bind(this);
+        }
+        return h;
+      },
+      configurable: true
+    });
+  }
+  for (const method of Object.keys(schema.methods)) {
+    const fn = schema.methods[method];
+    if (schema.tree.hasOwnProperty(method)) {
+      throw new Error('You have a method and a property in your schema both ' +
+        'named "' + method + '"');
+    }
+
+    // Avoid making custom methods if user sets a method to itself, e.g.
+    // `schema.method(save, Document.prototype.save)`. Can happen when
+    // calling `loadClass()` with a class that `extends Document`. See gh-12254
+    if (typeof fn === 'function' &&
+        Model.prototype[method] === fn) {
+      delete schema.methods[method];
+      continue;
+    }
+
+    if (schema.reserved[method] &&
+        !get(schema, `methodOptions.${method}.suppressWarning`, false)) {
+      utils.warn(`mongoose: the method name "${method}" is used by mongoose ` +
+        'internally, overwriting it may cause bugs. If you\'re sure you know ' +
+        'what you\'re doing, you can suppress this error by using ' +
+        `\`schema.method('${method}', fn, { suppressWarning: true })\`.`);
+    }
+    if (typeof fn === 'function') {
+      model.prototype[method] = fn;
+    } else {
+      apply(method, schema);
+    }
+  }
+
+  // Recursively call `applyMethods()` on child schemas
+  model.$appliedMethods = true;
+  for (const key of Object.keys(schema.paths)) {
+    const type = schema.paths[key];
+    if (type.$isSingleNested && !type.caster.$appliedMethods) {
+      applyMethods(type.caster, type.schema);
+    }
+    if (type.$isMongooseDocumentArray && !type.Constructor.$appliedMethods) {
+      applyMethods(type.Constructor, type.schema);
+    }
+  }
+};

node_modules/mongoose/lib/helpers/model/applyStaticHooks.js

@@ -0,0 +1,71 @@
+'use strict';
+
+const middlewareFunctions = require('../query/applyQueryMiddleware').middlewareFunctions;
+const promiseOrCallback = require('../promiseOrCallback');
+
+module.exports = function applyStaticHooks(model, hooks, statics) {
+  const kareemOptions = {
+    useErrorHandlers: true,
+    numCallbackParams: 1
+  };
+
+  hooks = hooks.filter(hook => {
+    // If the custom static overwrites an existing query middleware, don't apply
+    // middleware to it by default. This avoids a potential backwards breaking
+    // change with plugins like `mongoose-delete` that use statics to overwrite
+    // built-in Mongoose functions.
+    if (middlewareFunctions.indexOf(hook.name) !== -1) {
+      return !!hook.model;
+    }
+    return hook.model !== false;
+  });
+
+  model.$__insertMany = hooks.createWrapper('insertMany',
+    model.$__insertMany, model, kareemOptions);
+
+  for (const key of Object.keys(statics)) {
+    if (hooks.hasHooks(key)) {
+      const original = model[key];
+
+      model[key] = function() {
+        const numArgs = arguments.length;
+        const lastArg = numArgs > 0 ? arguments[numArgs - 1] : null;
+        const cb = typeof lastArg === 'function' ? lastArg : null;
+        const args = Array.prototype.slice.
+          call(arguments, 0, cb == null ? numArgs : numArgs - 1);
+        // Special case: can't use `Kareem#wrap()` because it doesn't currently
+        // support wrapped functions that return a promise.
+        return promiseOrCallback(cb, callback => {
+          hooks.execPre(key, model, args, function(err) {
+            if (err != null) {
+              return callback(err);
+            }
+
+            let postCalled = 0;
+            const ret = original.apply(model, args.concat(post));
+            if (ret != null && typeof ret.then === 'function') {
+              ret.then(res => post(null, res), err => post(err));
+            }
+
+            function post(error, res) {
+              if (postCalled++ > 0) {
+                return;
+              }
+
+              if (error != null) {
+                return callback(error);
+              }
+
+              hooks.execPost(key, model, [res], function(error) {
+                if (error != null) {
+                  return callback(error);
+                }
+                callback(null, res);
+              });
+            }
+          });
+        }, model.events);
+      };
+    }
+  }
+};

node_modules/mongoose/lib/helpers/model/applyStatics.js

@@ -0,0 +1,13 @@
+'use strict';
+
+/**
+ * Register statics for this model
+ * @param {Model} model
+ * @param {Schema} schema
+ * @api private
+ */
+module.exports = function applyStatics(model, schema) {
+  for (const i in schema.statics) {
+    model[i] = schema.statics[i];
+  }
+};

node_modules/mongoose/lib/helpers/model/castBulkWrite.js

@@ -0,0 +1,240 @@
+'use strict';
+
+const getDiscriminatorByValue = require('../../helpers/discriminator/getDiscriminatorByValue');
+const applyTimestampsToChildren = require('../update/applyTimestampsToChildren');
+const applyTimestampsToUpdate = require('../update/applyTimestampsToUpdate');
+const cast = require('../../cast');
+const castUpdate = require('../query/castUpdate');
+const setDefaultsOnInsert = require('../setDefaultsOnInsert');
+
+/**
+ * Given a model and a bulkWrite op, return a thunk that handles casting and
+ * validating the individual op.
+ * @param {Model} originalModel
+ * @param {Object} op
+ * @param {Object} [options]
+ * @api private
+ */
+
+module.exports = function castBulkWrite(originalModel, op, options) {
+  const now = originalModel.base.now();
+
+  if (op['insertOne']) {
+    return (callback) => {
+      const model = decideModelByObject(originalModel, op['insertOne']['document']);
+
+      const doc = new model(op['insertOne']['document']);
+      if (model.schema.options.timestamps && options.timestamps !== false) {
+        doc.initializeTimestamps();
+      }
+      if (options.session != null) {
+        doc.$session(options.session);
+      }
+      op['insertOne']['document'] = doc;
+
+      if (options.skipValidation || op['insertOne'].skipValidation) {
+        callback(null);
+        return;
+      }
+
+      op['insertOne']['document'].$validate().then(
+        () => { callback(null); },
+        err => { callback(err, null); }
+      );
+    };
+  } else if (op['updateOne']) {
+    return (callback) => {
+      try {
+        if (!op['updateOne']['filter']) {
+          throw new Error('Must provide a filter object.');
+        }
+        if (!op['updateOne']['update']) {
+          throw new Error('Must provide an update object.');
+        }
+
+        const model = decideModelByObject(originalModel, op['updateOne']['filter']);
+        const schema = model.schema;
+        const strict = options.strict != null ? options.strict : model.schema.options.strict;
+
+        _addDiscriminatorToObject(schema, op['updateOne']['filter']);
+
+        if (model.schema.$timestamps != null && op['updateOne'].timestamps !== false) {
+          const createdAt = model.schema.$timestamps.createdAt;
+          const updatedAt = model.schema.$timestamps.updatedAt;
+          applyTimestampsToUpdate(now, createdAt, updatedAt, op['updateOne']['update'], {});
+        }
+
+        applyTimestampsToChildren(now, op['updateOne']['update'], model.schema);
+
+        if (op['updateOne'].setDefaultsOnInsert !== false) {
+          setDefaultsOnInsert(op['updateOne']['filter'], model.schema, op['updateOne']['update'], {
+            setDefaultsOnInsert: true,
+            upsert: op['updateOne'].upsert
+          });
+        }
+
+        op['updateOne']['filter'] = cast(model.schema, op['updateOne']['filter'], {
+          strict: strict,
+          upsert: op['updateOne'].upsert
+        });
+
+        op['updateOne']['update'] = castUpdate(model.schema, op['updateOne']['update'], {
+          strict: strict,
+          overwrite: false,
+          upsert: op['updateOne'].upsert
+        }, model, op['updateOne']['filter']);
+      } catch (error) {
+        return callback(error, null);
+      }
+
+      callback(null);
+    };
+  } else if (op['updateMany']) {
+    return (callback) => {
+      try {
+        if (!op['updateMany']['filter']) {
+          throw new Error('Must provide a filter object.');
+        }
+        if (!op['updateMany']['update']) {
+          throw new Error('Must provide an update object.');
+        }
+
+        const model = decideModelByObject(originalModel, op['updateMany']['filter']);
+        const schema = model.schema;
+        const strict = options.strict != null ? options.strict : model.schema.options.strict;
+
+        if (op['updateMany'].setDefaultsOnInsert !== false) {
+          setDefaultsOnInsert(op['updateMany']['filter'], model.schema, op['updateMany']['update'], {
+            setDefaultsOnInsert: true,
+            upsert: op['updateMany'].upsert
+          });
+        }
+
+        if (model.schema.$timestamps != null && op['updateMany'].timestamps !== false) {
+          const createdAt = model.schema.$timestamps.createdAt;
+          const updatedAt = model.schema.$timestamps.updatedAt;
+          applyTimestampsToUpdate(now, createdAt, updatedAt, op['updateMany']['update'], {});
+        }
+
+        applyTimestampsToChildren(now, op['updateMany']['update'], model.schema);
+
+        _addDiscriminatorToObject(schema, op['updateMany']['filter']);
+
+        op['updateMany']['filter'] = cast(model.schema, op['updateMany']['filter'], {
+          strict: strict,
+          upsert: op['updateMany'].upsert
+        });
+
+        op['updateMany']['update'] = castUpdate(model.schema, op['updateMany']['update'], {
+          strict: strict,
+          overwrite: false,
+          upsert: op['updateMany'].upsert
+        }, model, op['updateMany']['filter']);
+      } catch (error) {
+        return callback(error, null);
+      }
+
+      callback(null);
+    };
+  } else if (op['replaceOne']) {
+    return (callback) => {
+      const model = decideModelByObject(originalModel, op['replaceOne']['filter']);
+      const schema = model.schema;
+      const strict = options.strict != null ? options.strict : model.schema.options.strict;
+
+      _addDiscriminatorToObject(schema, op['replaceOne']['filter']);
+      try {
+        op['replaceOne']['filter'] = cast(model.schema, op['replaceOne']['filter'], {
+          strict: strict,
+          upsert: op['replaceOne'].upsert
+        });
+      } catch (error) {
+        return callback(error, null);
+      }
+
+      // set `skipId`, otherwise we get "_id field cannot be changed"
+      const doc = new model(op['replaceOne']['replacement'], strict, true);
+      if (model.schema.options.timestamps) {
+        doc.initializeTimestamps();
+      }
+      if (options.session != null) {
+        doc.$session(options.session);
+      }
+      op['replaceOne']['replacement'] = doc;
+
+      if (options.skipValidation || op['replaceOne'].skipValidation) {
+        op['replaceOne']['replacement'] = op['replaceOne']['replacement'].toBSON();
+        callback(null);
+        return;
+      }
+
+      op['replaceOne']['replacement'].$validate().then(
+        () => {
+          op['replaceOne']['replacement'] = op['replaceOne']['replacement'].toBSON();
+          callback(null);
+        },
+        error => {
+          callback(error, null);
+        }
+      );
+    };
+  } else if (op['deleteOne']) {
+    return (callback) => {
+      const model = decideModelByObject(originalModel, op['deleteOne']['filter']);
+      const schema = model.schema;
+
+      _addDiscriminatorToObject(schema, op['deleteOne']['filter']);
+
+      try {
+        op['deleteOne']['filter'] = cast(model.schema,
+          op['deleteOne']['filter']);
+      } catch (error) {
+        return callback(error, null);
+      }
+
+      callback(null);
+    };
+  } else if (op['deleteMany']) {
+    return (callback) => {
+      const model = decideModelByObject(originalModel, op['deleteMany']['filter']);
+      const schema = model.schema;
+
+      _addDiscriminatorToObject(schema, op['deleteMany']['filter']);
+
+      try {
+        op['deleteMany']['filter'] = cast(model.schema,
+          op['deleteMany']['filter']);
+      } catch (error) {
+        return callback(error, null);
+      }
+
+      callback(null);
+    };
+  } else {
+    return (callback) => {
+      callback(new Error('Invalid op passed to `bulkWrite()`'), null);
+    };
+  }
+};
+
+function _addDiscriminatorToObject(schema, obj) {
+  if (schema == null) {
+    return;
+  }
+  if (schema.discriminatorMapping && !schema.discriminatorMapping.isRoot) {
+    obj[schema.discriminatorMapping.key] = schema.discriminatorMapping.value;
+  }
+}
+
+/**
+ * gets discriminator model if discriminator key is present in object
+ * @api private
+ */
+
+function decideModelByObject(model, object) {
+  const discriminatorKey = model.schema.options.discriminatorKey;
+  if (object != null && object.hasOwnProperty(discriminatorKey)) {
+    model = getDiscriminatorByValue(model.discriminators, object[discriminatorKey]) || model;
+  }
+  return model;
+}

node_modules/mongoose/lib/helpers/model/discriminator.js

@@ -0,0 +1,213 @@
+'use strict';
+
+const Mixed = require('../../schema/mixed');
+const applyBuiltinPlugins = require('../schema/applyBuiltinPlugins');
+const clone = require('../clone');
+const defineKey = require('../document/compile').defineKey;
+const get = require('../get');
+const utils = require('../../utils');
+const mergeDiscriminatorSchema = require('../../helpers/discriminator/mergeDiscriminatorSchema');
+
+const CUSTOMIZABLE_DISCRIMINATOR_OPTIONS = {
+  toJSON: true,
+  toObject: true,
+  _id: true,
+  id: true,
+  virtuals: true,
+  methods: true
+};
+
+/*!
+ * ignore
+ */
+
+module.exports = function discriminator(model, name, schema, tiedValue, applyPlugins, mergeHooks) {
+  if (!(schema && schema.instanceOfSchema)) {
+    throw new Error('You must pass a valid discriminator Schema');
+  }
+
+  mergeHooks = mergeHooks == null ? true : mergeHooks;
+
+  if (model.schema.discriminatorMapping &&
+      !model.schema.discriminatorMapping.isRoot) {
+    throw new Error('Discriminator "' + name +
+        '" can only be a discriminator of the root model');
+  }
+
+  if (applyPlugins) {
+    const applyPluginsToDiscriminators = get(model.base,
+      'options.applyPluginsToDiscriminators', false) || !mergeHooks;
+    // Even if `applyPluginsToDiscriminators` isn't set, we should still apply
+    // global plugins to schemas embedded in the discriminator schema (gh-7370)
+    model.base._applyPlugins(schema, {
+      skipTopLevel: !applyPluginsToDiscriminators
+    });
+  } else if (!mergeHooks) {
+    applyBuiltinPlugins(schema);
+  }
+
+  const key = model.schema.options.discriminatorKey;
+
+  const existingPath = model.schema.path(key);
+  if (existingPath != null) {
+    if (!utils.hasUserDefinedProperty(existingPath.options, 'select')) {
+      existingPath.options.select = true;
+    }
+    existingPath.options.$skipDiscriminatorCheck = true;
+  } else {
+    const baseSchemaAddition = {};
+    baseSchemaAddition[key] = {
+      default: void 0,
+      select: true,
+      $skipDiscriminatorCheck: true
+    };
+    baseSchemaAddition[key][model.schema.options.typeKey] = String;
+    model.schema.add(baseSchemaAddition);
+    defineKey({
+      prop: key,
+      prototype: model.prototype,
+      options: model.schema.options
+    });
+  }
+
+  if (schema.path(key) && schema.path(key).options.$skipDiscriminatorCheck !== true) {
+    throw new Error('Discriminator "' + name +
+        '" cannot have field with name "' + key + '"');
+  }
+
+  let value = name;
+  if ((typeof tiedValue === 'string' && tiedValue.length) || tiedValue != null) {
+    value = tiedValue;
+  }
+
+  function merge(schema, baseSchema) {
+    // Retain original schema before merging base schema
+    schema._baseSchema = baseSchema;
+    if (baseSchema.paths._id &&
+        baseSchema.paths._id.options &&
+        !baseSchema.paths._id.options.auto) {
+      schema.remove('_id');
+    }
+
+    // Find conflicting paths: if something is a path in the base schema
+    // and a nested path in the child schema, overwrite the base schema path.
+    // See gh-6076
+    const baseSchemaPaths = Object.keys(baseSchema.paths);
+    const conflictingPaths = [];
+
+    for (const path of baseSchemaPaths) {
+      if (schema.nested[path]) {
+        conflictingPaths.push(path);
+        continue;
+      }
+
+      if (path.indexOf('.') === -1) {
+        continue;
+      }
+      const sp = path.split('.').slice(0, -1);
+      let cur = '';
+      for (const piece of sp) {
+        cur += (cur.length ? '.' : '') + piece;
+        if (schema.paths[cur] instanceof Mixed ||
+            schema.singleNestedPaths[cur] instanceof Mixed) {
+          conflictingPaths.push(path);
+        }
+      }
+    }
+
+    mergeDiscriminatorSchema(schema, baseSchema);
+
+    // Clean up conflicting paths _after_ merging re: gh-6076
+    for (const conflictingPath of conflictingPaths) {
+      delete schema.paths[conflictingPath];
+    }
+
+    // Rebuild schema models because schemas may have been merged re: #7884
+    schema.childSchemas.forEach(obj => {
+      obj.model.prototype.$__setSchema(obj.schema);
+    });
+
+    const obj = {};
+    obj[key] = {
+      default: value,
+      select: true,
+      set: function(newName) {
+        if (newName === value || (Array.isArray(value) && utils.deepEqual(newName, value))) {
+          return value;
+        }
+        throw new Error('Can\'t set discriminator key "' + key + '"');
+      },
+      $skipDiscriminatorCheck: true
+    };
+    obj[key][schema.options.typeKey] = existingPath ? existingPath.options[schema.options.typeKey] : String;
+    schema.add(obj);
+
+    schema.discriminatorMapping = { key: key, value: value, isRoot: false };
+
+    if (baseSchema.options.collection) {
+      schema.options.collection = baseSchema.options.collection;
+    }
+    const toJSON = schema.options.toJSON;
+    const toObject = schema.options.toObject;
+    const _id = schema.options._id;
+    const id = schema.options.id;
+
+    const keys = Object.keys(schema.options);
+    schema.options.discriminatorKey = baseSchema.options.discriminatorKey;
+    const userProvidedOptions = schema._userProvidedOptions;
+    for (const _key of keys) {
+      if (!CUSTOMIZABLE_DISCRIMINATOR_OPTIONS[_key]) {
+        // Use `schema.options` in `deepEqual()` because of `discriminatorKey`
+        // set above. We don't allow customizing discriminator key, always
+        // overwrite. See gh-9238
+        if (_key in userProvidedOptions && !utils.deepEqual(schema.options[_key], baseSchema.options[_key])) {
+          throw new Error('Can\'t customize discriminator option ' + _key +
+            ' (can only modify ' +
+            Object.keys(CUSTOMIZABLE_DISCRIMINATOR_OPTIONS).join(', ') +
+            ')');
+        }
+      }
+    }
+    schema.options = clone(baseSchema.options);
+
+    for (const _key of Object.keys(userProvidedOptions)) {
+      schema.options[_key] = userProvidedOptions[_key];
+    }
+    if (toJSON) schema.options.toJSON = toJSON;
+    if (toObject) schema.options.toObject = toObject;
+    if (typeof _id !== 'undefined') {
+      schema.options._id = _id;
+    }
+    schema.options.id = id;
+    if (mergeHooks) {
+      schema.s.hooks = model.schema.s.hooks.merge(schema.s.hooks);
+    }
+    if (applyPlugins) {
+      schema.plugins = Array.prototype.slice.call(baseSchema.plugins);
+    }
+    schema.callQueue = baseSchema.callQueue.concat(schema.callQueue);
+    delete schema._requiredpaths; // reset just in case Schema#requiredPaths() was called on either schema
+  }
+
+  // merges base schema into new discriminator schema and sets new type field.
+  merge(schema, model.schema);
+
+  if (!model.discriminators) {
+    model.discriminators = {};
+  }
+
+  if (!model.schema.discriminatorMapping) {
+    model.schema.discriminatorMapping = { key: key, value: null, isRoot: true };
+  }
+  if (!model.schema.discriminators) {
+    model.schema.discriminators = {};
+  }
+
+  model.schema.discriminators[name] = schema;
+
+  if (model.discriminators[name] && !schema.options.overwriteModels) {
+    throw new Error('Discriminator with name "' + name + '" already exists');
+  }
+
+  return schema;
+};

node_modules/mongoose/lib/helpers/model/pushNestedArrayPaths.js

@@ -0,0 +1,15 @@
+'use strict';
+
+module.exports = function pushNestedArrayPaths(paths, nestedArray, path) {
+  if (nestedArray == null) {
+    return;
+  }
+
+  for (let i = 0; i < nestedArray.length; ++i) {
+    if (Array.isArray(nestedArray[i])) {
+      pushNestedArrayPaths(paths, nestedArray[i], path + '.' + i);
+    } else {
+      paths.push(path + '.' + i);
+    }
+  }
+};