Module: pgm-settings

This is a node module to retrieve program settings from various json document sources. The source objects are merged into a single node object. Any node object can be used as a set of default parameters, thus allowing setting collections to be chained.

The source json documents may contain C/C++ style comments that are removed before parsing.

The getProgramSettings({options}) is an async function that can also return a node promise.

Configuration Sources

• default settings object
• specified json file
• program environment variable
• program startup argument

Usage

const getSettings = require('pgm-settings').getProgramSettings;
var theSettings = await getSettings({options})

The working function in the module is getProgramSettings({options}). The entry point for the module is an un-named async function that calls getProgramSettings().

The Options:

Option = name of option Type = typeof option Seq = processing sequence Description = purpose of option

| OPTION | TYPE | SEQ | DESCRIPTION | |--|--|--|--| | default: | object | 1 | default configuration object | | file: | string | 2 | A filepath to a json file | | env: | string | 3 | The environment variable name | | arg: | string | 4 | The program arguement name | | argenv: | string | 5 | Composite env/arg name |

If the {options} is empty, then the following is assumed:

env: 'SETTINGS'       env.SETTINGS can be a filepath or json document
arg: 'settings'       parsed as --settings=filepath
                      or --settings filepath

The argenv: argument is ignored if either env: or arg: are specified.

env = argenv.toUpperCase()
arg = argenv.toLowerCase()

JSON Comments - C/C++

Source json files may have C/C++ style comments. The comments are removed before the json document is parsed.

/* A C style comment
   that supports multiple lines.
*/
// A C++ comment that extends to current end-of-line.

Example Files - for your own tests

mytest.js
settings-env.json
settings-file.json
settings.json

Mocha Test Suite: (npm test)

test/testing.js		// the regression test file
test/settings-arg.json	// configuration file for program argument testing
test/settings-env.json	// configuration file for program environment testing
test/settings-file.json	// configuration file for options {file: filename.json} testing

Testing getProgramSettings
    ✓ No Configurations Supplied
        getProgramSettings()
    ✓ File Configuration Supplied
        getProgramSettings({file:'settings-file.json'})
    ✓ Default Configuration Supplied
        getProgramSettings({default:{object}})
    ✓ Default+File Configuration Supplied
        getProgramSettings({default:{object},file:'settings-file.json'})
    ✓ Environment Default SETTINGS:settings-env.json Configuration Supplied
        process.env[SETTINGS]='settings-env.json';
        getProgramSettings();
    ✓ Environment Default SETTINGS:<json-document> Configuration Supplied
        process.env[SETTINGS]='{a json document}';
        getProgramSettings();
    ✓ Environment NODE_SETTINGS:settings-env.json Configuration Supplied
        process.env[NODE_SETTINGS]='settings-env.json';
        getProgramSettings({env:'NODE_SETTINGS'})
    ✓ Environment NODE_SETTINGS:<json-document> Configuration Supplied
        process.env[NODE_SETTINGS]='{a json document}';
        getProgramSettings({env:'NODE_SETTINGS'})
    ✓ Program Arg: --settings=settings-arg.json Configuration File
        process.argv.push('--node_settings=settings-arg.json');
        getProgramSettings({arg:'node_settings'})
    ✓ Program argenv: Node_Settings - Combined Configurations
        getProgramSettings({argenv:'Node_Settings'})
        // implies env:'NODE_SETTINGS' and arg:'node_settings'

Support

You can use github resources to help resolve issues.

The author email is not read on a regular basis.