- [Instructor] Promises give us another option of…how to work with asynchronous code.…Promises return an object which promise to do some work.…This object has separate callbacks…for success and for failures.…This lets us work with asynchronous code…in a much more synchronous way.…A really nice feature is that…Promises can be combined into dependency chains.…To demonstrate these features,…let's convert censor example to use Promises…so that we can see how it cleans up our code a bit.…Let's scroll down to our message post function,…and on line 28, instead of passing a callback…of the first parameter,…we'll pass nothing, and then we'll add .then,…and this will execute if there are no errors.…
And then we can place our callback…inside the then function.…And so now, this function, as a callback,…is placed inside then.…Since we got rid of the error parameter,…we'll need to check for errors using another method.…We can chain on a catch function at the end.…
And then we'll pass on a callback to handle our errors…so that it will take in an error,…
Author
Updated
4/5/2019Released
11/7/2017- Asynchronous tasks and callbacks
- Benefits and features of JavaScript
- Managing third-party packages with npm
- Node.js frameworks
- Static serving with Express
- Creating a browser app
- Exploring databases
- Saving data to MongoDB with Mongoose
- Error handling and debugging
- Simple tests and async tests
Skill Level Beginner
Duration
Views
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Introduction
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Welcome41s
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1. Introduction to Node
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Download and install Node1m 28s
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2. Understanding npm: Node Package Manager
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Write your own module2m 18s
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3. Reading and Writing Files
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Read from files4m 31s
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Access directories1m 6s
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Write to a file2m 46s
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4. Exploring Web Frameworks
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Node.js frameworks1m 23s
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Express1m 6s
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Socket.io55s
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5. Building Your Demo App Chat Client for the Browser
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Static serving with Express5m 30s
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Create your browser app8m 43s
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Create your Socket.io event1m 59s
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6. Exploring Databases
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Types of data frameworks2m 2s
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Set up MongoDB1m 46s
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Mongoose2m 59s
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7. Improving Asynchronous Code
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Nested callbacks3m 27s
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Promises7m 14s
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Async/await2m 44s
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8. Error Handling and Debugging
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Try/catch2m 6s
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Finally1m 40s
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Editor debugging4m 14s
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9. Testing
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Simple test with Jasmine4m 33s
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Async test with Jasmine5m 33s
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Conclusion
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Next steps1m 24s
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Video: Promises