resolve-options

What is resolve-options?

The resolve-options npm package is designed to help developers manage and resolve configuration options for their applications or libraries. It provides a structured way to define defaults, validate types, and handle option resolution logic in a centralized manner.

What are resolve-options's main functionalities?

Defining and resolving options

This feature allows developers to define a schema for options including types and default values, and then resolve them against user-provided values. The example shows how to define a simple configuration and resolve it.

const resolveOptions = require('resolve-options');

const config = {
  option: {
    type: 'string',
    default: 'default value'
  }
};

const resolved = resolveOptions(config, { option: 'custom value' });
console.log(resolved.option); // Outputs: 'custom value'

Type validation

This feature ensures that the options provided by the user match the expected type defined in the configuration schema. The example demonstrates type validation where a type mismatch throws an error.

const resolveOptions = require('resolve-options');

const config = {
  option: {
    type: 'number',
    default: 10
  }
};

try {
  const resolved = resolveOptions(config, { option: 'not a number' });
} catch (error) {
  console.error(error); // Outputs: Error indicating the type mismatch
}

Other packages similar to resolve-options

yargs

Yargs helps in building interactive command line tools, by parsing arguments and generating an elegant user interface. It's more focused on CLI arguments parsing compared to resolve-options which is more generic in handling any kind of options.

config

The config package is used for managing configuration settings across different deployment environments. Unlike resolve-options, which is about resolving options dynamically, config is more about static configuration management.

README

resolve-options

Resolve an options object based on configuration.

Usage

// This example assumes a Vinyl file

var createResolver = require('resolve-options');

var config = {
  cwd: {
    type: 'string',
    default: process.cwd,
  },
  sourcemaps: {
    type: 'boolean',
    default: false,
  },
  since: {
    type: ['date', 'number'],
  },
  read: {
    type: 'boolean',
  },
};

var options = {
  sourcemaps: true,
  since: Date.now(),
  read: function (file) {
    return file.extname !== '.mp4';
  },
};

var resolver = createResolver(config, options);

var cwd = resolver.resolve('cwd', file);
// cwd === process.cwd()

var sourcemaps = resolver.resolve('sourcemaps', file);
// sourcemaps === true

var read = resolver.resolve('read', file);
// Given .mp4, read === false
// Given .txt, read === true

API

createResolver([config,] [options])

Takes a config object that describes the options to accept/resolve and an options object (usually passed by a user) to resolve against the config. Returns a resolver that contains a resolve method for realtime resolution of options.

The config object takes the following structure:

config {
  [optionKey] {
    type // string, array or function
    default // any value or function
  }
}

Each option is represented by its optionKey in the config object. It must be an object with a type property.

The type property must be a string, array or function which will be passed to the value-or-function module (functions will be bound to the resolver to allow for dependent options).

A default property may also be specified as a fallback if the option isn't available or is invalid. The default value can be any value or a function (functions will be bound to the resolver to allow for dependent defaults). Note: default values are not type-validated by the value-or-function module.

resolver.resolve(optionKey, [...arguments])

Takes an optionKey string and any number of arguments to apply if an option is a function. Returns the resolved value for the optionKey.

resolver.resolveConstant(optionKey)

Like resolve, but only returns a value if the option is constant (not a function).

License

MIT

Changelog

2.0.0 (2022-06-24)

⚠ BREAKING CHANGES

• Normalize repository, dropping node <10.13 support (#5)

Features

• Add resolveConstant method on a resolver (#3) (02439c4)

Miscellaneous Chores

• Normalize repository, dropping node <10.13 support (#5) (0ddd042)