fastconf

fastconf

npm install fastconf

import fastconf from 'fastconf'

// Fastconf is a convenience utility to quickly generate a
// configuration object based on the provided lookup object.
//
// It expects that all keys you give it are unique (will
// never map to the same key in the returned object), and that
// all keys are required unless specified optional.
const config = fastconf({
  // Prefix, useful for not having to repeat yourself.
  // If you have a prefix of 'NICE_', and have a required key 'FOO_BAR',
  // then fastconf will expect there to be an environment variable
  // with the key 'NICE_FOO_BAR', and will add it to the object
  // with the key fooBar.
  prefix: 'NICE_',

  // Whether to normalize names of the environment variables or not.
  // If true, keys like FOO_BAR will be named fooBar in the returned
  // configuration object.
  //
  // Defaults to true.
  normalizeNames: true,

  // Whether to consider a required key as existing only if it's undefined.
  // Otherwise, the following rule applies:
  // * The key does not exist if the environment variable is an empty string
  //
  // Defaults to false.
  strictExistence: false,

  // An array of [key, options] values.
  keys: [
    ['FOO_BAR', {
      // Key type. Can be either String, Number, or Boolean.
      //
      // The String type returns values as-is.
      //
      // The Number type parses the string as a number. If the
      // parsed number is NaN, then fastconf will throw an error.
      //
      // The Boolean type tried to parse the string as a boolean.
      // It must be one of the following values:
      //  false: '0', 'false' (case insensitive), 'no' (case insensitive)
      //  true: '1', 'true' (case insensitive), 'yes' (case insensitive)
      //
      // Defaults to String.
      type: Number,

      // Whether to normalize the name for this individual key.
      // See normalizeNames's documentation for more info.
      //
      // Defaults to normalizeNames's value.
      normalizeName: false,

      // Whether to use strict existence checking for this individual
      // key. See strictExistence's documentation for more info.
      strictExistence: true,

      // Default value, which can be any value. If a default value
      // is provided (not undefined), then the key is no longer required, and
      // fastconf will not throw an error if the value does not
      // exist.
      defaultValue: 0
    }],
    ['MORE_THINGS', {type: String, defaultValue: null}]
  ]
}, {
  // The optional second object provided are any "namespaces"
  // that you want to provide. These can be nested.
  // For example, if you have the 'xbpf' namespace, with its
  // own set of keys and values, the returned
  // object will look like this:
  //
  // {
  //   FOO_BAR: 123,
  //   moreThings: null,
  //   xbpf: {
  //    zigZag: 2929
  //   }
  // }
  //
  // This is useful for separate prefixes, and general organization.
  // Note that the object gets run through another call to fastconf(),
  // with the difference of it reusing the already determined environment
  // object.
  xbpf: {
    prefix: 'XBPF_',
    keys: [
      ['ZIG_ZAG', {type: Number}]
    ]
  }
}, {
  // If you wish to, you can provide your own key-value environment map.
  // Requires that all values for the keys are strings.
  //
  // Otherwise, fastconf will use process.env
  'NICE_FOO_BAR': '123',
  'XBPF_ZIG_ZAG': '2929'
})