standardgalactic / u

μ is a JavaScript library for encoding/decoding state (JavaScript object) in URL

μ

Without μ: http://app.com/url#%7B%22lookingFor%22:%22bride%22,%22age%22:%5B25,30%5D,%22religion%22:%22Hindu%22,%22motherTongue%22:%22Bengali%22,%22onlyProfileWithPhoto%22:true%7D

With μ: http://app.com/url#bHhc9I-aqa

μ is a JavaScript library for encoding/decoding state (JavaScript object) in URL. Define a spec for the state, based on which the encoding is done. Manage the state with versioning.

Example

Import the library

import {fromJson, encode, decode} from "u";

Define the spec.

var spec = {
        lookingFor: ['oneOf', 'bride', 'groom'],
        age: ['tuple', ['integer'] /* min */, ['integer'] /* max */],
        religion: ['oneOf', 'Hindu', 'Muslim', 'Christian', 'Sikh', 'Parsi', 'Jain', 'Buddhist', 'Jewish', 'No Religion', 'Spiritual', 'Other'],
        motherTongue: ['oneOf', 'Assamese', 'Bengali', 'English', 'Gujarati', 'Hindi', 'Kannada', 'Konkani', 'Malayalam', 'Marathi', 'Marwari', 'Odia', 'Punjabi', 'Sindhi', 'Tamil', 'Telugu', 'Urdu'],
        onlyProfileWithPhoto: ['boolean']
};

var v1 = fromJson(1, spec);

Encode the object/state.

var encodedv1 = encode(v1, {lookingFor: 'bride', age: [25, 30], religion: 'Hindu', motherTongue: 'Bengali', onlyProfileWithPhoto: true});
//=> 'bHhc9I-aqa'
decode([v1], encodedv1) //=> {lookingFor: 'bride', age: [25, 30], religion: 'Hindu', motherTongue: 'Bengali', onlyProfileWithPhoto: true});

Update your spec, as your application state space grows. Use versioning to encode/decode state.

var newSpec = _.extend({}, spec, {
        maritialStatus: ['oneOf', "Doesn't Matter", 'Never Married', 'Divorced', 'Widowed', 'Awaiting Divorce', 'Annulled']
});
var v2 = fromJson(2, newSpec, function (old) {
        old.maritialStatus = "Doesn't Matter";
        return old;
});

decode([v1, v2], encodedv1) //=> {lookingFor: 'bride', age: [25, 30], religion: 'Hindu', motherTongue: 'Bengali', onlyProfileWithPhoto: true, maritialStatus: "Doesn't Matter"});
var encodedv2 = encode(v2, {lookingFor: 'bride', age: [25, 30], religion: 'Hindu', motherTongue: 'Bengali', onlyProfileWithPhoto: true, maritialStatus: 'Never Married'});
//=> 'cHlc9I-aHaa'
decode([v1, v2], encodedv2) //=> {lookingFor: 'bride', age: [25, 30], religion: 'Hindu', motherTongue: 'Bengali', onlyProfileWithPhoto: true, maritialStatus: 'Never Married'});

API

fromJson(version, spec, [migrate])

version - spec version number
spec - used to define the structure and domain of the data.

structure
object is defined using { key: specForValue, ... }
array is defined using ['array', specForValue ]
tuple is defined using ['tuple', specForValueAtIndexZero, specForValueAtIndexOne, ...]

domain
domain is defined using [domainName, arg1, arg2, ...]

Domain	Args	Description
oneOf	allowed values	can be considered similar to enum. As we only encode the index position, the value could be anything
integer		any integer
boolean		true or false
fixedchar	Size of the string	fixed length string
varchar		variable length string

migrate - a function that will get called in case where you decode an object encoded using older spec. For example, there are three versions v1, v2, v3 and you try to decode the string encoded using v1, then the migrate method in v2 and v3 will get called with the decoded value.

encode(coder, object)

coder - coder created using fromJson
object - object that needs to encoded

decode(coders, blob)

coders - array of coder.
blob - the string that is returned by encode.