- Jan 2024
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mongoosejs.com mongoosejs.com
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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
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- Nov 2023
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www.uspto.gov www.uspto.gov
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This overarching goal is stated in the U.S. Constitution, Article I section 8, clause 8, “The Congress shall have Power ... To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries.”
Then, the article quote the U.S. Constitution, Article I section 8, clause 8, and then explains that, in the 18th century, this constitutional law gave the congress the power to grant exclusive rights to authors and inventors for their work, in order to boost creativity and innovation in the USA (U.S. Const., 1787). Later, the article claims that in the 1975, the U.S. Constitution, Article I section 8, clause 8 keep having the purpose of fostering innovation and creativity in the society, throughout economic incentive. Subsequently, the article supports this statement by quoting the law "Twentieth Century Music Corp. v. Aiken," which was created in 1975 with the purpose of boosting creativity and innovation in society throughout the economic incentive of assuring that creators receive a payment for their intellectual property that equates to the cost of producing it.
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- Sep 2022
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metalblueberry.github.io metalblueberry.github.io
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Some people eventually realize that the code quality is important, but they lack of the time to do it. This is the typical situation when you work under pressure or time constrains. It is hard to explain to you boss that you need another week to prepare your code when it is “already working”. So you ship the code anyway because you can not afford to spent one week more.
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To see if you are writing good code, you can question yourself. how long it will take to fully transfer this project to another person? If the answer is uff, I don’t know… a few months… your code is like a magic scroll. most people can run it, but no body understand how it works. Strangely, I’ve seen several places where the IT department consist in dark wizards that craft scrolls to magically do things. The less people that understand your scroll, the more powerfully it is. Just like if life were a video game.
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Code explains what and how Documentation explains why.
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So make sure to write your documentation, but do not explain your spells.
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This is so clear that you don’t even need comments to explain it.
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Another type of comments are the ones trying to explain a spell.
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Do not explain your spells, rewrite them.
Tags
- source code: comments: explain why, not what or how
- pressure
- work: manager who understands what you do
- +1.0
- documentation: good
- I agree
- time constraints
- hard to explain
- write code that humans can understand
- answer the "why?"
- if you have to explain it, rewrite it to be simpler
- +0.8
Annotators
URL
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- May 2022
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wordpress.com wordpress.com
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"I didn't fully understand it at the time, but throughout my time as a freshman at Boston College I've realized that I have the power to alter myself for the better and broaden my perspective on life. For most of my high school experience, I was holding to antiquated thoughts that had an impact on the majority of my daily interactions. Throughout my life, growing up as a single child has affected the way am in social interactions. This was evident in high school class discussions, as I did not yet have the confidence to be talkative and participate even up until the spring term of my senior year."
Tags
- Introduction p.1
- In this annotation, I choose to expand on my introduction. Before I explain why I chose the words I did, I should mention that my first draft failed to meet one of the assignment's primary requirements: a "Story like" structure. Finally, I decided to rework my introduction because my first draft did not begin with a clear beginning. Instead, I started by describing the fundamental context of the encounter before detailing my previous experiences. To improve my final edit, I made sure I described my experiences and/or how I felt before they occurred.
- (Major Essay) Introduction paragraph
Annotators
URL
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- Apr 2022
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stackoverflow.com stackoverflow.com
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Check both execution plans (using explain (analyze, verbose) and you'll see
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- Feb 2022
- Aug 2021
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github.com github.com
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I hope you'll forgive me for defaulting to the documentation: I think it will do a better job of explaining it than me.
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- Mar 2021
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gitlab.gnome.org gitlab.gnome.org
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I am wondering if it wasn't faster for maintainers/developers who know the glib code to just provide a fix instead of writing comments on this issue.
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- Sep 2020
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stackoverflow.com stackoverflow.com
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do I really have to do something like that in order to have my local modules working? it's quite impracticable to explain it to a team! there's nothing a little bit more straightforward?
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github.com github.com
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Please focus on explaining the motivation so that if this RFC is not accepted, the motivation could be used to develop alternative solutions. In other words, enumerate the constraints you are trying to solve without coupling them too closely to the solution you have in mind.
Tags
- okay for proposal to not be accepted
- iterative process: building on previous attempts/work
- defining the problem clearly is as valuable coming up with specific implementation/solution
- contribution guidelines: should explain motivation for change
- iterative process
- answer the "why?"
Annotators
URL
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- Nov 2019
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github.com github.com
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Description explains the issue / use-case resolved
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- Oct 2017
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arvrjourney.com arvrjourney.com
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factors
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vivo
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- Feb 2016
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learning.ccsso.org learning.ccsso.org
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Explain major differences between poems, drama, and prose, and refer to the structural elements of poems (e.g., verse, rhythm, meter) and drama (e.g., casts of characters, settings, descriptions, dialogue, stage directions) when writing or speaking about a text.
For this standard, students would have to read a variety of poems, plays and prose to understand the structural differences. Then the students must use the structural knowledge to properly write and speak about poems and plays. A good play for this standard would be Annie and a good collections of poems to understand structure would be from poet Roald Dahl.
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- Apr 2014
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www.newschallenge.org www.newschallenge.org
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science will produce improved results and better serve the community.
How will the results be improved and in what way will the community be better served?
I expect you explain how later in the document and provide examples, but to strengthen the intro and capture your readers give the a teaser of what's to come if they continue reading.
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