README

simple-map

simple-map is a super small utility function to map one object to another based on a key-value-pair map or a function.

Examples

mapping with key-value pairs

var map = require('simple-map');

var person = { 
    firstName: "John",
    lastName: "Doe"
};

var m = {
    "firstName": "first_name",
    "lastName": "last_name"
};

map(person, m); // { "first_name": "John", "last_name": "Doe" }

mapping with a function

function convertKey(k) {
    var m = { "x": "a", "y": "b", "z": "c" };
    return m[k];
}

map({"x": 1, "y": 2, "z": 3}, convertKey); // { "a": 1, "b": 2, "c": 3 }

FYI - repattern is a nice complement to simple-map

var map = require('simple-map');
var repattern = require('repattern');

var columnCase = repattern.make('cam$_');
map({'firstName': 'John', 'lastName': 'Doe'}, columnCase); // {'first_name': 'John', 'last_name': 'Doe'}	

only mapping certain keys

In some cases, its useful to map with a function, but restrict to only specific properties. You can pass an array of keys to include for this.

var person = {
    first_name: "John",
    last_name: "Doe",
    password: "a"
}

function convertKey(k) {
    return k.toUpperCase().replace("_", "");
}

map(person, convertKey, ["first_name", "last_name"]); // { "FIRSTNAME": "John", "LASTNAME": "Doe" }

map.make

map.make is super useful. It creates a curried function with an enclosed map and include list. You can use this with array#map to map objects within a collection.

var peopleRecords = [{"first_name": "John", "last_name": "Doe", "password", "a"}];
var personMapper = map.make(convertKey, ['first_name', 'last_name']);
var dtos = peopleRecords.map(personMapper);

install

npm install simple-map

use

var map = require('simple-map');