26 Matching Annotations
  1. Jan 2024
    1. 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 the Animal 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 the Animal schema. When you create an instance of the Animal model (e.g., a dog), you can then call findSimilarTypes on that instance to find other animals with the same type. The method uses the this.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 the Animal model.

      Certainly! Let's go through each part and explain it in simple terms: ### 1. `this` in Mongoose: - **What is `this`?** In JavaScript, `this` refers to the current context or object. In Mongoose, particularly within methods and middleware functions, `this` represents the instance (document) the function is currently operating on. - **Why is it used?** `this` is used to access and modify the properties of the current document. For example, in a Mongoose method, `this` allows you to refer to the fields of the specific document the method is called on. ### 2. Example: Let's use the `userSchema.pre("save", ...)`, which is a Mongoose middleware, as an example: ```javascript userSchema.pre("save", async function (next) { if (!this.isModified("password")) { next(); } else { this.password = await bcrypt.hash(this.password, 10); next(); } }); ``` - **Explanation in Simple Words:** - Imagine you have a system where users can sign up and set their password. - Before saving a new user to the database, you want to ensure that the password is securely encrypted (hashed) using a library like `bcrypt`. - The `userSchema.pre("save", ...)` is a special function that runs automatically before saving a user to the database. - In this function: - `this.isModified("password")`: Checks if the password field of the current user has been changed. - If the password is not modified, it means the user is not updating their password, so it just moves on to the next operation (saving the user). - If the password is modified, it means a new password is set or the existing one is changed. In this case, it uses `bcrypt.hash` to encrypt (hash) the password before saving it to the database. - The use of `this` here is crucial because it allows you to refer to the specific user document that's being saved. It ensures that the correct password is hashed for the current user being processed. In summary, `this` in Mongoose is a way to refer to the current document or instance, and it's commonly used to access and modify the properties of that document, especially in middleware functions like the one demonstrated here for password encryption before saving to the database.

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    1. I feel that the current design area should be a key part of the workflow on any work item, not just type of designs. As a PM I don't schedule designs independently. It's odd to open and close a design issue when it doesn't deliver value to the customer.
  2. Jun 2023
  3. Mar 2023
  4. Oct 2022
    1. The problem is that the caller may write yield instead of block.call. The code I have given is possible caller's code. Extended method definition in my library can be simplified to my code above. Client provides block passed to define_method (body of a method), so he/she can write there anything. Especially yield. I can write in documentation that yield simply does not work, but I am trying to avoid that, and make my library 100% compatible with Ruby (alow to use any language syntax, not only a subset).

      An understandable concern/desire: compatibility

      Added new tag for this: allowing full syntax to be used, not just subset

  5. Aug 2022
    1. I'm building a Rails API with a separate web frontend app as "just another API client" (various smartphone apps to follow as well). In the previous "monolithic" version of the service, where all the server side was rolled into one Rails app
  6. Sep 2021
    1. Let's not get over-excited. Actually, we're only part-way there; you can compile this code with the TypeScript compiler.... But is that enough?I bundle my TypeScript with ts-loader and webpack. If I try and use my new exciting import statement above with my build system then disappointment is in my future. webpack will be all like "import whuuuuuuuut?"You see, webpack doesn't know what we told the TypeScript compiler in the tsconfig.json.
  7. Jun 2021
  8. Mar 2021
  9. Feb 2021
    1. which entails computer programming (process of writing and maintaining the source code), but also encompasses a planned and structured process from the conception of the desired software to its final manifestation
  10. Jan 2021
    1. Most users frankly don’t care how software is packaged. They don’t understand the difference between deb / rpm / flatpak / snap. They just want a button that installs Spotify so they can listen to their music.
    2. What’s the use of ie. snap libreoffice if it can’t access documents on a samba server in my workplace ? Should I really re-organize years of storage and work in my office for being able to use snap ? A too high price to pay, for the moment.
  11. Nov 2020
    1. This is Sass based, and therefore doesn't require Svelte components

      Just because we could make Svelte wrapper components for each Material typography [thing], doesn't mean we should.

      Compare:

      • material-ui [react] did make wrapper components for typography.

        • But why did they? Is there a technical reason why they couldn't just do what svelte-material-ui did (as in, something technical that Svelte empowers/allows?), or did they just not consider it?
      • svelte-material-ui did not.

        • And they were probably wise to not do so. Just reuse the existing work from the Material team so that there's less work for you to keep in sync and less chance of divergence.
  12. Oct 2020
  13. Sep 2020
  14. Apr 2020
    1. Surely all Uber drivers were submitted to the same labor regime, but those who had to endure it as a means to survive were predominantly people of color.

      This is also true of companies like Instacart, GrubHub,etc.

  15. Jul 2019
  16. Apr 2017