shargs-example-sync-deepthought-config-env-argv is a sample application of shargs 🦈.

See the shargs github repository for more details!

Setup

$ git clone https://github.com/Yord/shargs-example-sync-deepthought-config-env-argv.git
$ cd shargs-example-sync-deepthought-config-env-argv
$ npm i
$ chmod +x ./deepThought

Example

This repository is an example how to use several layers of configuration with shargs. The program first reads configurations from config.json, then from environment variables, and finally from command-line arguments. Later configurations override earlier ones. The program can be found in the deepThought script.

Run the Example

The example may be run with different parameters:

Printing Usage Documentation

Providing a --help flag:

$ ./deepThought --help

Or providing the DT_HELP=true environment variable:

$ DT_HELP=true ./deepThought

Prints the following text to the console:

deepThought [-a|--answer] [-h|--help]                                           
deepThought ask [--format] [--no-html] [-h|--help] (<question>)                 
                                                                                
-a, --answer=<number>    The answer. [default: 42]                              
-h, --help               Print this help message and exit.                      
ask                      Ask a question. [required]                             
    --format=<json|xml>  Respond either with json or xml. [default: json]       
    --no-html            Removes HTML tags.                                     
    -h, --help           Print this help message and exit.                      
    <question>           State your question. [required]                        
                                                                                
Deep Thought was created to come up with the Answer to The Ultimate Question of 
Life, the Universe, and Everything.                                             

Providing ask --help:

$ ./deepThought ask --help

Or providing DT_ASK__HELP=true:

$ DT_ASK__HELP=true ./deepThought

Prints text in a different usage format:

deepThought ask [--format] [--no-html] [-h|--help] (<question>)                 
                                                                                
--format=<json|xml> [default: json]                                             
    Respond either with json or xml.                                            
--no-html                                                                       
    Removes HTML tags.                                                          
-h, --help                                                                      
    Print this help message and exit.                                           
<question> [required]                                                           
    State your question.                                                        
                                                                                
Deep Thought was created to come up with the Answer to The Ultimate Question of 
Life, the Universe, and Everything.                                             

The Answer to the Ultimate Question

Providing more complex arguments:

$ DT_ANSWER=43 DT_ASK__NO_HTML=true ./deepThought ask --no-html "What is life?"

Prints the following text to the console:

The answer is: 43
{
  "answer": 43,
  "ask": {
    "format": "json",
    "_": [],
    "html": false,
    "question": "What is life?"
  },
  "_": []
}

Please note, the following:

1. {"format": "json"} comes from config.json and is neither overridden by environment variables nor command-line arguments.
2. {"answer": 43} comes from DT_ANSWER=43, which overrides {"answer": 42} from config.json.
3. {"html": false} comes from ask --no-html, which overrides DT_ASK__NO_HTML=true.
4. {"question": "What is life?"} comes from ask "What is life?".

Error Output

Providing no ask command:

$ ./deepThought --answer 23

Prints the following error:

RequiredOptionMissing: An option that is marked as required has not been provided.

Providing a wrong --format:

$ ./deepThought ask --format csv

Prints the following error:

RequiredOptionMissing: An option that is marked as required has not been provided.
ValueRestrictionsViolated: A value lies outside the allowed values of an option.

Reporting Issues

Please report issues in the shargs tracker!

License

shargs-example-sync-deepthought-config-env-argv is MIT licensed.