n_

Node.js REPL with lodash

Why?

Sometimes we use the Node.js REPL interface to experiment with code. Wouldn’t it be great to have that interface with lodash required by default?

Installation

$ npm install -g n_

Usage

$ n_
n_ >

lodash is now attached to the REPL context as _, so just use it:

n_ > _.compact([0, 1, false, 2, '', 3]);
[ 1, 2, 3 ]
n_ >

FP mode

It is possible to use lodash’s functional programming variant lodash/fp:

$ n_ --fp
n_ > _.map(function(v) { return v * 2; }, [1, 2, 3]);
[ 2, 4, 6 ]
n_ >

Strict mode

It is possible to enable strict mode in Node.js >= 4.x:

$ n_ --use_strict
n_ >

Repl specificities

Commands

Some commands are available to facilitate some operations, and are host under .lodash repl command:

• .lodash fp: switch to lodash/fp
• .lodash vanilla: switch to vanilla lodash mode
• .lodash reset: switch to initial lodash mode
• .lodash swap: switch to the other lodash mode (vanilla/fp)
• .lodash current: output current lodash flavor in use
• .lodash version: output lodash version in use

and the .lodash help to have more details about lodash repl commands

__ as last evaluated expression

Special character _ refer to the lodash instance, and cannot hold value of last expression. To provide the same feature, __ was introduced:

n_ > 10 + 2
12
n_ > 'number '+ __
'number 12'

Configuration options

Aside --fp and --use_strict/--use-strict, some other options are available either as CLI flags, or via environment variables.(with a trailing _N_)

The two main feature you can control is History persistance and Prompt Theme.

Flag	aliases	Env variable	Description	Default
--history-path	--history, history-file	_N_HISTORY_PATH	Location of repl history file	~/.n_repl_history
--prompt.symbol		_N_PROMPT__SYMBOL	Symbol to use as $ prompt	>
--prompt.name		_N_PROMPT__NAME	Name for the prompt	n_
--prompt.color.name		_N_PROMPT__COLOR__NAME	Color for prompt name n_	blue
--prompt.color.symbol		_N_PROMPT__COLOR__SYMBOL	Color for prompt symbol	red
--prompt.color.flavor		_N_PROMPT__COLOR__FLAVOR	Color for section of prompt about lodash flavor in use	cyan
--prompt.color.help		_N_PROMPT__COLOR__HELP	Color for section of prompt about lodash flavor in use	green

About styling, valid colors are: black, red, green, yellow, blue, magenta, cyan, white,gray, and dim.

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Enjoy! 🚀