flopmang

Flag-Option Manager for Grunt: framework for converting grunt task-options into CLI flags for child processes

Getting started

What this isn't: this is not a grunt plugin.

What this is: a utility to make writing and extending plugins that delegate to command line APIs easier. It provides a simple interface for mapping grunt-task-options to command line flags.

Installation:

npm install --save flopmang

var ArgUtil = require('flopmang');

Quick example:

The code below illustrates how to set up a simple grunt multiTask that will run npm install in any directory you wish. When using configuring the task in the Gruntfile, the user will be able to specify the following options:

• global default: undefined: translated to -g if set to truey
• saveDev default: undefined: translated to --save-dev by underscore.string.dasherize
• dir default: process.cwd: translated to cwd option when spawning child process package default: undefined: required. Only the value is appended to the args

var ArgUtil = require('flopmang');
var async = require('async');

module.exports = function (grunt) {
    grunt.registerMulitTask(
        'npmInstall',
        'runs npm install in any directory'
        function () {
            var argConfigs = [
                {
                    option: 'global',
                    flag: '-g'
                },
                {
                    option: 'saveDev',
                },
                {
                    option: 'dir',
                    defaultValue: process.cwd,
                    useAsFlag:false,
                },
                {
                    option: 'package',
                    required: true,
                    useAsFlag: false,
                    useValue: true
                },
            ];
            var argUtil = new ArgUtil(this, argConfigs);

            var args = ['npm', 'install'].concat(argUtil.getArgFlags());

            var done = async();

            var options = argUtil.options;

            var spawnOpts = {};

            if (options.dir) {
                spawnOpts.cwd = options.dir;
            }

            var cp = grunt.util.spawn({
                args: args,
                opts: spawnOpts,
                function spawnEnd (err, result, code) {
                    if (err) {
                        throw err
                    }
                    grunt.log.writeln('\n' + result.stdout);
                    done();
                }
            });
        }
    );

The argConfigs array contains multiple objects that describe options, and how they should be mapped to CLI flags by getArgFlags();

Using this multitask in a Gruntfile:

grunt.initConfig({
    npmInstall{
        flopmang: {
            options: {
                package: 'flopmang',
                dir: '/home/dylancwood/project',
                global: false,
                saveDev: true
            }
        }
    }
});

API

argConfig

The following properties are available to configure each option/argument:

option

Type: string Default value: undefined Required

The name of the option (e.g. 'global' or 'package');

customFlagFn

Type: function Default value: undefined

A function to be used to generate a custom flag value. This function is given one argument: the current arg object. This overrides useAsFlag. example:

...
{
    option: 'customOption',
    customFlagFn: function (arg) {
        if (arg.value) {
            return arg.option + '-' + arg.value;
        }
        return null;
    }
}
...

customValueFn

Type: function Default value: undefined

A function to be used to generate a custom value string. This function is given one argument: the current arg object. This overrides useValue. See above for example.

defaultValue

Type: any Default value: undefined

The default value for the option if the user does not specify it

flag

Type: string Default value: undefined

If set, and useAsFlag is true, this value will be used as the flag. This is overridden by the value returned by customFlagFn.

required

Type: boolean Default value: false

If set to true, an error will be thrown if the value of the option is null, an empty string (''), or undefined. For more complex validation, see validationFn

useAsFlag

Type: boolean Default value: true

If set to true, then the option label will be included in the flags unless the option's value is a falsy (excluding zero). This is overridden by the customFlagFn.

useDasherize

Type: boolean Default value: true

If set to true, then the option label will be prepended with -- and processed using underscore.string's dasherize function. (e.g. oCamelCase will be converted to --o-camel-case)

useValue

Type: boolean Default value: false

If set to true, then the value of the option will be included in the flags unless the value is a falsy (excluding zero). This is overridden by the customValueFn.

validationFn

Type: function Default value: undefined

The option will be validated using this function. This function may either throw an error, or return false to indicate that the option is invalid. Returning true indicates that the option is valid. This function is given one argument: the current arg object. example:

...
{
    option: 'customOption',
    validationFn: function (arg) {
        if (arg.value === undefined) {
            raise new Error('must provide a ' + arg.option);
        }
        if (arg.value > 10 && arg.value < 100) {
            return true
        }
        return false;
    }
}
...

value

Type: any Default value: undefined

This should never be used. Though it is possible to set the value here, it will be overridden by the defaultValue before the constructor returns.

Constructor

var flopmang = new FlOpMang(task, configs);

The constructor takes two arguments:

task

Type: object

The current grunt task. This is used to extend the default values with the user-provided options at run-time. Depending on the context from which you are calling the constructor, you can use this, or grunt.task.current.

configs

Type: array

An array of argConfig configuration objects as described above. Example:

var configs = [
    { option: 'option1' },
    { option: 'option2', useValue: true }
];
var flopMang = new FlopMang(grunt.task.current, configs);

getArgFlags

The getArgFlags method returns an array of flags that have been created according to the configs and user-specified options.

Example:

Suppose that we have the following configs:

[
    { option: 'option1'},
    { option: 'option2', flag: '-o', defaultValue: true },
    { option: 'option3', useAsFlag: false, useValue: true }
]

And suppose that the config for the current task/target looks like this:

options: {
    option1: true,
    option3: 100
}

getArgFlags will produce the following output:

['--option1', '-o', 100]

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using Grunt.