- Jan 2024
-
mongoosejs.com mongoosejs.com
-
Instance methods Instances of Models are documents. Documents have many of their own built-in instance methods. We may also define our own custom document instance methods. // define a schema const animalSchema = new Schema({ name: String, type: String }, { // Assign a function to the "methods" object of our animalSchema through schema options. // By following this approach, there is no need to create a separate TS type to define the type of the instance functions. methods: { findSimilarTypes(cb) { return mongoose.model('Animal').find({ type: this.type }, cb); } } }); // Or, assign a function to the "methods" object of our animalSchema animalSchema.methods.findSimilarTypes = function(cb) { return mongoose.model('Animal').find({ type: this.type }, cb); }; Now all of our animal instances have a findSimilarTypes method available to them. const Animal = mongoose.model('Animal', animalSchema); const dog = new Animal({ type: 'dog' }); dog.findSimilarTypes((err, dogs) => { console.log(dogs); // woof }); Overwriting a default mongoose document method may lead to unpredictable results. See this for more details. The example above uses the Schema.methods object directly to save an instance method. You can also use the Schema.method() helper as described here. Do not declare methods using ES6 arrow functions (=>). Arrow functions explicitly prevent binding this, so your method will not have access to the document and the above examples will not work.
Certainly! Let's break down the provided code snippets:
1. What is it and why is it used?
In Mongoose, a schema is a blueprint for defining the structure of documents within a collection. When you define a schema, you can also attach methods to it. These methods become instance methods, meaning they are available on the individual documents (instances) created from that schema.
Instance methods are useful for encapsulating functionality related to a specific document or model instance. They allow you to define custom behavior that can be executed on a specific document. In the given example, the
findSimilarTypes
method is added to instances of theAnimal
model, making it easy to find other animals of the same type.2. Syntax:
Using
methods
object directly in the schema options:javascript const animalSchema = new Schema( { name: String, type: String }, { methods: { findSimilarTypes(cb) { return mongoose.model('Animal').find({ type: this.type }, cb); } } } );
Using
methods
object directly in the schema:javascript animalSchema.methods.findSimilarTypes = function(cb) { return mongoose.model('Animal').find({ type: this.type }, cb); };
Using
Schema.method()
helper:javascript animalSchema.method('findSimilarTypes', function(cb) { return mongoose.model('Animal').find({ type: this.type }, cb); });
3. Explanation in Simple Words with Examples:
Why it's Used:
Imagine you have a collection of animals in your database, and you want to find other animals of the same type. Instead of writing the same logic repeatedly, you can define a method that can be called on each animal instance to find similar types. This helps in keeping your code DRY (Don't Repeat Yourself) and makes it easier to maintain.
Example:
```javascript const mongoose = require('mongoose'); const { Schema } = mongoose;
// Define a schema with a custom instance method const animalSchema = new Schema({ name: String, type: String });
// Add a custom instance method to find similar types animalSchema.methods.findSimilarTypes = function(cb) { return mongoose.model('Animal').find({ type: this.type }, cb); };
// Create the Animal model using the schema const Animal = mongoose.model('Animal', animalSchema);
// Create an instance of Animal const dog = new Animal({ type: 'dog', name: 'Buddy' });
// Use the custom method to find similar types dog.findSimilarTypes((err, similarAnimals) => { console.log(similarAnimals); }); ```
In this example,
findSimilarTypes
is a custom instance method added to theAnimal
schema. When you create an instance of theAnimal
model (e.g., a dog), you can then callfindSimilarTypes
on that instance to find other animals with the same type. The method uses thethis.type
property, which refers to the type of the current animal instance. This allows you to easily reuse the logic for finding similar types across different instances of theAnimal
model.
Tags
Annotators
URL
-
- Nov 2022
-
blog.chain.link blog.chain.link
-
What Is a Blockchain Oracle? A blockchain oracle is a secure piece of middleware that facilitates communication between blockchains and any off-chain system, including data providers, web APIs, enterprise backends, cloud providers, IoT devices, e-signatures, payment systems, other blockchains, and more. Oracles take on several key functions: Listen – monitor the blockchain network to check for any incoming user or smart contract requests for off-chain data. Extract – fetch data from one or multiple external systems such as off-chain APIs hosted on third-party web servers. Format – format data retrieved from external APIs into a blockchain readable format (input) and/or making blockchain data compatible with an external API (output). Validate – generate a cryptographic proof attesting to the performance of an oracle service using any combination of data signing, blockchain transaction signing, TLS signatures, Trusted Execution Environment (TEE) attestations, or zero-knowledge proofs. Compute – perform some type of secure off-chain computation for the smart contract, such as calculating a median from multiple oracle submissions or generating a verifiable random number for a gaming application. Broadcast – sign and broadcast a transaction on the blockchain in order to send data and any corresponding proof on-chain for consumption by the smart contract. Output (optional) – send data to an external system upon the execution of a smart contract, such as relaying payment instructions to a traditional payment network or triggering actions from a cyber-physical system.
Seems related to the paradox of information systems. Add to Anki deck
-
- Sep 2022
- Jun 2022
-
www.ifour.co www.ifour.co
-
The battle of firmware vs middleware is fierce. Firmware is a particular class of computer software that gives low-level command over the particular hardware of the device.
-
- Aug 2021
-
-
<small><cite class='h-cite via'>ᔥ <span class='p-author h-card'>Daphne Keller </span> in Project MUSE - The Future of Platform Power: Making Middleware Work (<time class='dt-published'>08/01/2021 11:18:47</time>)</cite></small>
-
-
-
-
Francis Fukuyama et al., Middleware for Dominant Digital Platforms: A Technological Solution to a Threat to Democracy, Stanford Cyber Policy Center, 3, https://fsi-live.s3.us-west-1.amazonaws.com/s3fs-public/cpc-middleware_ff_v2.pdf.
-
If we cannot afford real, diverse, and independent assessment, we will not realize the promise of middleware.
-
Facebook deploys tens of thousands of people to moderate user content in dozens of languages. It relies on proprietary machine-learning and other automated tools, developed at enormous cost. We cannot expect [End Page 169] comparable investment from a diverse ecosystem of middleware providers. And while most providers presumably will not handle as much content as Facebook does, they will still need to respond swiftly to novel and unpredictable material from unexpected sources. Unless middleware services can do this, the value they provide will be limited, as will users' incentives to choose them over curation by the platforms themselves.
Does heavy curation even need to exist? If a social company were able to push a linear feed of content to people without the algorithmic forced engagement, then the smaller, fringe material wouldn't have the reach. The majority of the problem would be immediately solved with this single feature.
-
Second, how is everyone going to get paid? Without a profit motive for middleware providers, the magic will not happen, or it will not happen at large enough scale. Something about business models—or, at a minimum, the distribution of ads and ad revenue—will have to change. That leaves the two thorny issues I do know a fair amount about: curation costs and user privacy.
-
Before we can execute on the middleware vision, I see at least four problems to be solved. Two of those concern matters beyond my ken, but I will flag them here for others to consider.
-
Fukuyama's work, which draws on both competition analysis and an assessment of threats to democracy, joins a growing body of proposals that also includes Mike Masnick's "protocols not platforms," Cory Doctorow's "adversarial interoperability," my own "Magic APIs," and Twitter CEO Jack Dorsey's "algorithmic choice."
Nice overview of work in the space for fixing monopoly in social media space the at the moment. I hadn't heard about Fukuyama or Daphne Keller's versions before.
I'm not sure I think Dorsey's is actually a thing. I suspect it is actually vaporware from the word go.
IndieWeb has been working slowly at the problem as well.
-
Francis Fukuyama has called "middleware": content-curation services that could give users more control over the material they see on internet platforms such as Facebook or Twitter.
Tags
- hw-middleware
- want to read
- algorithmic choice
- problems
- curation
- social media machine guns
- definitions
- economics
- middleware
- filtering
- wordnik
- algorithmic feeds
- read
- diversity
- monopolies
- freedom of speech
- social media regulation
- content curation
- First Amendment
- Francis Fukuyama
- social media
- Mike Masnick
- Magic APIs
- government regulation
- democracy
- adversarial interoperability
Annotators
URL
-
- Apr 2021
-
github.com github.com
-
This gem uses a Rack middleware to clear the store object after every request, but that doesn't translate well to background processing with Sidekiq. A companion library, request_store-sidekiq creates a Sidekiq middleware that will ensure the store is cleared after each job is processed, for security and consistency with how this is done in Rack.
-
- Feb 2021
-
github.com github.com
-
Instead of dealing with a mix of before_filters, Rack-middlewares, controller code and callbacks, an endpoint is just another activity and allows to be customized with the well-established Trailblazer mechanics.
-
- Dec 2020
-
-
// app/middleware/cache.js,`use`ed in app/server.js import LRU from 'lru-cache'; const _cache = new LRU({ max: 500, maxAge: 1000 * 60 * 60 }); async function cache(req, res, next) { req.cache = _cache; next(); }
Tags
Annotators
URL
-
- Nov 2020
-
www.stevejgordon.co.uk www.stevejgordon.co.uk
-
AllowAnonymousAttribute
-
- Oct 2020
-
jackwhiting.co.uk jackwhiting.co.uk
-
In this code, we have another function in the middle which allows us to pass through both ctx (context) and a next function call
-
- Dec 2019
-
survivejs.com survivejs.com
-
To make some of this possible, we had to create our webpack configuration API, called webpack-chain. As you may know, webpack exposes a low-level configuration format, but this format isn't well-suited for merging configuration deterministically across middleware, or even across many projects. With webpack-chain, we expose a chainable or fluent API for aggregating a webpack configuration which is much more deterministic.
-
Neutrino utilizes webpack under the hood for building projects by augmenting it with knowledge about build middleware. Neutrino middleware are discrete pieces of webpack configuration that use a custom configuration API. You can compose many of these middleware together into custom presets, and each will modify the build accordingly.
-
-
neutrinojs.org neutrinojs.org
- Nov 2019
-
docs.silverstripe.org docs.silverstripe.org
-
If you really want to be sure your customisation gets loaded first or last, you can use * as your before or after reference.
controlling order
-
before and after also accept arrays of constraints.
controlling order
-
Much like the configuration layer, we need to specify a name for this transformation. This will help other modules negotiate their priority over the injector in relation to yours.
-
Instead of overriding a service with your own implementation, you enhance an existing service with your own concerns. This pattern is known as middleware.
-
Middleware works a lot like a decorator. It doesn't alter the original API of the service, but it can augment it with new features and concerns. This has the inherent advantage of allowing all thidparty code to have an influence over the behaviour, state, and UI of a component.
-
- Apr 2017
-
simpleisbetterthancomplex.com simpleisbetterthancomplex.com