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Solution: Launch a custom REPL from a command

From: Node.js Essential Training

Video: Solution: Launch a custom REPL from a command

Here's my solution to the challenge. I now have a flight repl, I can create flight objects, and they're automatically displayed in my console. I can also use the triggerArrive and triggerDepart functions. So let's take a look at how I did this. In index.js, I'm starting out with a hash bang, this command locates Node for us, so that we can run our script. Next, I require the repl module, and I also require the local flight module that we've been working with. Then, I create a prompt, based off the repl module.

Solution: Launch a custom REPL from a command

Here's my solution to the challenge. I now have a flight repl, I can create flight objects, and they're automatically displayed in my console. I can also use the triggerArrive and triggerDepart functions. So let's take a look at how I did this. In index.js, I'm starting out with a hash bang, this command locates Node for us, so that we can run our script. Next, I require the repl module, and I also require the local flight module that we've been working with. Then, I create a prompt, based off the repl module.

Finally, I assign the flight function into the context of the prompt. Let's also take a look at package.json. I named this project flight, so that flight is the name of the command that I type. Then I also added index.js as the property for bin. When all of this was in place, I went to terminal, and I went to the path of the project. Then I used npm link to install the command. I'm going to start the command back up again. There's one pit fall that you want to avoid when you're creating objects with this flight module.

If I just call flight and don't pass an argument in, it's going to give an error. This function is expecting exactly one argument, so even if you pass in a blank object, it'll still work. So that's how you can create a repl, and make it available as a Command Line tool.

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Node.js Essential Training

52 video lessons · 12588 viewers

Joseph LeBlanc
Author

 
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  1. 3m 9s
    1. Welcome
      42s
    2. What you should know before watching this course
      57s
    3. Using the exercise files
      47s
    4. Using the challenges
      43s
  2. 18m 50s
    1. Why use Node.js?
      2m 1s
    2. Choosing a Node.js installation process
      4m 56s
    3. Installing Node.js on the Mac
      2m 5s
    4. Installing Node.js on Windows
      1m 43s
    5. Installing Node.js via Node Version Manager on Ubuntu Linux
      4m 45s
    6. Installing Node.js via Node Version Manager on a Mac
      3m 20s
  3. 13m 54s
    1. Exploring language additions to the V8 JavaScript engine
      3m 38s
    2. Understanding require() and modules
      6m 39s
    3. Understanding callback execution in the event loop
      3m 37s
  4. 12m 23s
    1. Initializing Node.js projects
      2m 37s
    2. Finding an NPM
      3m 30s
    3. Maintaining projects using the npm command
      6m 16s
  5. 21m 4s
    1. Creating modules with getters and setters
      6m 33s
    2. Understanding module caching and scopes
      6m 15s
    3. Implementing JavaScript creational patterns
      5m 8s
    4. Challenge: Leveraging module caching
      55s
    5. Solution: Leveraging module caching
      2m 13s
  6. 32m 27s
    1. Starting Express applications
      3m 42s
    2. Handling GET requests returning JSON
      3m 26s
    3. Navigating large datasets using request variables in routes
      5m 4s
    4. Modifying data through PUT requests
      4m 32s
    5. Supplying middleware to modify HTTP response headers
      4m 37s
    6. Generating HTML views in Jade
      8m 9s
    7. Challenge: List all records as JSON
      37s
    8. Solution: List all records as JSON
      2m 20s
  7. 25m 37s
    1. Evaluating unit testing methodologies
      3m 8s
    2. Isolating existing code for testing
      6m 47s
    3. Supplying helpers for test data
      2m 35s
    4. Writing unit tests with Mocha
      6m 5s
    5. Simulating HTTP requests with SuperTest
      7m 2s
  8. 28m 45s
    1. Connecting to MongoDB via Mongoose
      4m 16s
    2. Defining schemas for collections in Mongoose
      3m 47s
    3. Querying MongoDB collections
      5m 32s
    4. Persisting Express sessions through MongoDB and mongo-connect
      7m 6s
    5. Logging in to Express applications using Passport
      8m 4s
  9. 21m 47s
    1. Controlling the built-in REPL
      4m 18s
    2. Constructing a custom REPL
      5m 40s
    3. Receiving command-line arguments with Optimist
      6m 14s
    4. Building command-line tools
      3m 35s
    5. Challenge: Launch a custom REPL from a command
      41s
    6. Solution: Launch a custom REPL from a command
      1m 19s
  10. 15m 46s
    1. Emitting events and attaching listeners
      5m 32s
    2. Streaming chunked data through readable streams
      2m 33s
    3. Controlling readable streams
      1m 52s
    4. Piping readable data into writable streams
      2m 10s
    5. Handling duplex streams over TCP
      3m 39s
  11. 4m 6s
    1. Deploying projects to cloud hosting services
      2m 36s
    2. Finding Node.js resources
      1m 30s

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