12 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.


      ```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.




  2. Nov 2023
    1. But I do question why lib and not something in app is the common suggestion for classes/modules who do not fall into the default set of folders (models, controllers, jobs, etc). Is it just because it's what we've been doing for so long? To me feels like we're trying to shoehorn the lib folder into further being a kitchen sink (now holding rake tasks and miscellaneous classes), rather than just saying "your Ruby classes/modules go somewhere in app because they're application code".
  3. Jul 2021
    1. better to have had five stupid ideas than no ideas at all. And if somebody wrongly points out that your idea is stupid, it is even more important not to take offence: just explain gently why their dismissal of your idea is itself stupid


  4. Apr 2021
    1. Of course you must not use plain-text passwords and place them directly into scripts. You even must not use telnet protocol at all. And avoid ftp, too. I needn’t say why you should use ssh, instead, need I? And you also must not plug your fingers into 220 voltage AC-output. Telnet was chosen for examples as less harmless alternative, because it’s getting rare in real life, but it can show all basic functions of expect-like tools, even abilities to send passwords. BUT, you can use “Expect and Co” to do other things, I just show the direction.
  5. Mar 2021
    1. Loolu sa afeer la.

      C'est ton affaire.

      loolu -- that.

      sa -- your.

      afeer bi -- (French: "affair") case.

      la -- the (?).

  6. Feb 2021
    1. For branching out a separate path in an activity, use the Path() macro. It’s a convenient, simple way to declare alternative routes

      Seems like this would be a very common need: once you switch to a custom failure track, you want it to stay on that track until the end!!!

      The problem is that in a Railway, everything automatically has 2 outputs. But we really only need one (which is exactly what Path gives us). And you end up fighting the defaults when there are the automatic 2 outputs, because you have to remember to explicitly/verbosely redirect all of those outputs or they may end up going somewhere you don't want them to go.

      The default behavior of everything going to the next defined step is not helpful for doing that, and in fact is quite frustrating because you don't want unrelated steps to accidentally end up on one of the tasks in your custom failure track.

      And you can't use fail for custom-track steps becase that breaks magnetic_to for some reason.

      I was finding myself very in need of something like this, and was about to write my own DSL, but then I discovered this. I still think it needs a better DSL than this, but at least they provided a way to do this. Much needed.

      For this example, I might write something like this:

      step :decide_type, Output(Activity::Left, :credit_card) => Track(:with_credit_card)
      # Create the track, which would automatically create an implicit End with the same id.
      Track(:with_credit_card) do
          step :authorize
          step :charge

      I guess that's not much different than theirs. Main improvement is it avoids ugly need to specify end_id/end_task.

      But that wouldn't actually be enough either in this example, because you would actually want to have a failure track there and a path doesn't have one ... so it sounds like Subprocess and a new self-contained ProcessCreditCard Railway would be the best solution for this particular example... Subprocess is the ultimate in flexibility and gives us all the flexibility we need)

      But what if you had a path that you needed to direct to from 2 different tasks' outputs?

      Example: I came up with this, but it takes a lot of effort to keep my custom path/track hidden/"isolated" and prevent other tasks from automatically/implicitly going into those steps:

      class Example::ValidationErrorTrack < Trailblazer::Activity::Railway
        step :validate_model, Output(:failure) => Track(:validation_error)
        step :save,           Output(:failure) => Track(:validation_error)
        # Can't use fail here or the magnetic_to won't work and  Track(:validation_error) won't work
        step :log_validation_error, magnetic_to: :validation_error,
          Output(:success) => End(:validation_error), 
          Output(:failure) => End(:validation_error) 
      puts Trailblazer::Developer.render o
       {Trailblazer::Activity::Right} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=validate_model>
      #<Trailblazer::Activity::TaskBuilder::Task user_proc=validate_model>
       {Trailblazer::Activity::Left} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=log_validation_error>
       {Trailblazer::Activity::Right} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=save>
      #<Trailblazer::Activity::TaskBuilder::Task user_proc=save>
       {Trailblazer::Activity::Left} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=log_validation_error>
       {Trailblazer::Activity::Right} => #<End/:success>
      #<Trailblazer::Activity::TaskBuilder::Task user_proc=log_validation_error>
       {Trailblazer::Activity::Left} => #<End/:validation_error>
       {Trailblazer::Activity::Right} => #<End/:validation_error>

      Now attempt to do it with Path... Does the Path() have an ID we can reference? Or maybe we just keep a reference to the object and use it directly in 2 different places?

      class Example::ValidationErrorTrack::VPathHelper1 < Trailblazer::Activity::Railway
         validation_error_path = Path(end_id: "End.validation_error", end_task: End(:validation_error)) do
          step :log_validation_error
        step :validate_model, Output(:failure) => validation_error_path
        step :save,           Output(:failure) => validation_error_path
      o=Example::ValidationErrorTrack::VPathHelper1; puts Trailblazer::Developer.render o
       {Trailblazer::Activity::Right} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=validate_model>
      #<Trailblazer::Activity::TaskBuilder::Task user_proc=validate_model>
       {Trailblazer::Activity::Left} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=log_validation_error>
       {Trailblazer::Activity::Right} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=save>
      #<Trailblazer::Activity::TaskBuilder::Task user_proc=log_validation_error>
       {Trailblazer::Activity::Right} => #<End/:validation_error>
      #<Trailblazer::Activity::TaskBuilder::Task user_proc=save>
       {Trailblazer::Activity::Left} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=log_validation_error>
       {Trailblazer::Activity::Right} => #<End/:success>

      It's just too bad that:

      • there's not a Railway helper in case you want multiple outputs, though we could probably create one pretty easily using Path as our template
      • we can't "inline" a separate Railway acitivity (Subprocess "nests" it rather than "inlines")
    2. step :direct_debit

      I don't think we would/should really want to make this the "success" (Right) path and :credit_card be the "failure" (Left) track.

      Maybe it's okay to repurpose Left and Right for something other than failure/success ... but only if we can actually change the default semantic of those signals/outputs. Is that possible? Maybe there's a way to override or delete the default outputs?

  7. Sep 2020
    1. This is so common that ECMAScript 2020 recently added a new syntax to support this pattern!export * as utilities from "./utilities.js";This is a nice quality-of-life improvement to JavaScript, and TypeScript 3.8 implements this syntax. When your module target is earlier than es2020, TypeScript will output something along the lines of the first code snippet.
  8. Jan 2020
    1. to remember how to best fall down;

      Remember how our children learned to walk? Yeah, they didn't learn how to walk, they learned how to fall down.