show-help

node module helper to display help section given command line arguments

Install

npm i @maboiteaspam/show-help --save

Usage

function usage () {/*
    ...some text...
    ...about your program...
*/}
var pkg   = require('./package.json')
var help  = require('@maboiteaspam/show-help')(usage, process.argv, pkg)     // manage -h|--help
var debug = require('@maboiteaspam/set-verbosity')(pkg.name, process.argv);  // manage -v|--verbose [what?]
!argv['_'] && showHelp.print(usage, pkg) && showHelp.die();                  // manage some wrong invocation

Usage

process.argv

Using the node process.argv value

function usage () {/*
module name
        ...

    Usage
        ...

    Options
        ...

    Examples
        ...
*/}

var pkg       = require('./package.json')                           // always useful.
var showHelp  = require('./index.js')                               // load showHelp,
  .tpl('%name %version\n\t%description\n\n%usage')                  // set a different template.
  (usage, process.argv, pkg)                                        // Print help and quit,
                                                                    // if -h|--help.

//require('./index.js')(usage, process.argv, pkg)                   // one-liner

!argv['_']                                                          // if arguments are incorrect,
&& showHelp.print(usage, pkg)                                       // show help,
&& showHelp.die();                                                  // exit.

console.log('program execution')

Which then, can be invoked in such fashion

module-name -h
module-name --help

minimist

Using minimist module to pre parse values

function usage () {/*
module name
        ...

    Usage
        ...

    Options
        ...

    Examples
        ...
*/}
var pkg       = require('./package.json')                           // always useful.
var argv      = require('minimist')(process.argv.slice(2));         // parse args with minimist,
var showHelp  = require('./index.js')                               // load showHelp,
  .tpl('%name %version\n\t%description\n\n%usage')                  // set a different template.
  (usage, argv.h||argv.help, pkg)                                   // Print help and quit,
                                                                    // if -h|--help.

//require('./index.js')(usage, argv.h||argv.help, pkg)              // one-liner

!argv['_']                                                          // if arguments are incorrect,
&& showHelp.print(usage, pkg)                                       // show help,
&& showHelp.die();                                                  // exit.

console.log('program execution')

Which then, can be invoked in such fashion

module-name -h
module-name --help

Api

showHelp

showHelp is a function to display help and exit when needed, it returns showHelp for a fluent interface.

• showHelp(callable fn, object arg, object pkg, int code) void

When typeof(arg) is object, detect (-h|--help), and figures out if usage should be displayed and program killed.

pkg is object of package.json file.

• showHelp(callable fn, string arg, object pkg, int code) void

When typeof(arg) is string, and not falsy, it displays usage and kills the program with code.

pkg is object of package.json file.

• showHelp(callable fn, bool arg, object pkg, int code) void

When typeof(arg) is bool, and not falsy, it displays usage and kills the program with code.

pkg is object of package.json file.

showHelp.tpl

showHelp.tpl is a function to set a template to render usage, it returns showHelp for a fluent interface.

• showHelp(string newTpl) showHelp

set tpl to newTpl, then returns showHelp for chaining.

showHelp.raw

showHelp.raw is a function to parse a string as a command line input. It detects -h|--help and invoke showHelp.parsed. It returns true, if it has displayed help, otherwise false.

• showHelp.raw(callable fn, object pkg, string arg) bool

When arg.match(/-h|--help/) is not falsy, it renders and displays usage.

showHelp.parsed

showHelp.parsed is a function to invoke showHelp.print when arg is not falsy. It returns true, if it has displayed help, otherwise false.

• showHelp.parsed(callable fn, object pkg, string arg) bool

When arg is not falsy, it renders and displays usage.

showHelp.print

showHelp.print is a function to render template given multiline(fn) usage string and pkg object, then prints it on console.error. It returns true, always, for fluent interface with die().

• showHelp.print(callable fn, object pkg) true

Renders usage then print it on console.error.

showHelp.die

showHelp.die is a function to exist process

• showHelp.die(int exitCode) void

Exist process.

More

• https://github.com/sindresorhus/multiline
• https://nodejs.org/api/process.html#process_process_argv
• https://github.com/maboiteaspam/npi
• https://github.com/maboiteaspam/set-verbosity