map-abbrs

Creates a function that accepts specified strings (or abbreviations thereof) and returns corresponding specified output.

Can be used to map command-line arguments to functions, for example.

Installation

Requires Node.js 7.0.0 or above.

npm i map-abbrs

API

The module exports a single function.

Parameters

1. map (Map or Object): A dictionary of strings and values.
2. Optional: Object argument:
   • ci (boolean): Whether or not strings should be compared case-insensitively. Defaults to false.
   • elseCall (function): If provided, will be called with two arguments in the event that an input does not match any keys in the map. The first argument is a function that, when called, will defer to elseThrow and/or elseReturn if provided. (If elseCall cannot return a value, it should call this first argument and return its return value.) The second argument is the input that failed to match any single map key.
   • elseThrow (Error or string): An error to throw if an input does not match any single map key. A string will be converted to a RangeError. Only used if elseCall is not provided or defers.
   • elseReturn (any): A value to be returned if an input does not match any single map key. Only used if elseThrow is not provided and if elseCall is not provided or defers.

Return Value

Returns a function that accepts a single input argument. If this input matches a map key or is an abbreviation thereof, then the corresponding map value will be returned. Otherwise, fallback behavior will be determined by elseCall, elseThrow, and/or elseReturn.

Example

const mapAbbrs = require('map-abbrs')

const mapAbbr = mapAbbrs({
  example: 1,
  test: 2,
  testing: 3,
}, {
  elseCall: (fallback, input) => input === 'four' ? 4 : fallback(),
  elseThrow: 'Invalid or ambiguous value'
})

mapAbbr('example') // 1
mapAbbr('ex') // 1
mapAbbr('test') // 2
mapAbbr('testi') // 3
mapAbbr('t') // Uncaught RangeError: 'Invalid or ambiguous value'
mapAbbr('four') // 4
mapAbbr('other') // Uncaught RangeError: 'Invalid or ambiguous value'

Related

Inspired by abbrev.