/03-asynchronous-callbacks

CF 03: Parallel File Processing

Submission Instructions

  • Work in a fork of this repository
  • Work in a branch on your fork
  • Write all of your code in a directory named lab- + <your name> e.g. lab-susan
  • Open a pull request to this repository
  • Submit on canvas a question and observation, how long you spent, and a link to your pull request

Resources

Configuration

Configure the root of your repository with the following files and directories. Thoughtfully name and organize any aditional configuration or module files.

  • README.md - contains documentation
  • .gitignore - contains a robust .gitignore file
  • .eslintrc.json - contains the course linter configuration
  • .eslintignore - contains the course linter ignore configuration
  • package.json - contains npm package config
    • create a lint script for running eslint
    • create a test script for running tests
  • lib/ - contains module definitions
  • assets/ - contains the text files used by the program
  • __test__/ - contains unit tests

Feature Tasks

Reader Module

In the lib/ directory create a reader.js module that exports a single function. The reader module should take an array of three file paths and resolve a mapped array of strings loaded from each file using an error-first callback. The string data should be in the same order as the file path data (mapped). If an error occurs it should immediately reject the error using the callback and stop execution.

  • The reader module should have the function signature (paths, callback) => undefined
  • On a failure the reader module should invoke the callback with an error callback(error)
  • On success the reader module should invoke the callback with null as the first parameter, and the result as the second parameter callback(null, result)

Testing

Reader Module Tests

  • Use TDD describe and test methods to define descriptive tests
  • Each test callback should aim to test a small well defined feature of a function
  • Write tests to ensure the reader function rejects errors with invalid file paths
  • Write tests to ensure the reader function correctly resolves mapped string data for an array of file paths

Bonus 1pt

Write the reader function recursively so that it will be able to support 0 or more paths.

Documentation

In your README.md describe the exported values of each module you have defined. Every function description should include it's arity (expected number of parameters), the expected data for each parameter (data-type and limitations), and it's behavior (for both valid and invalid use). Feel free to write any additional information in your README.md.