Echo JS 0.11.0

I wanted a way to load in flow from configuration as well as to perform free form transformation of object->object.  Seemed a good fit for Lambda functions.

Looking at the existing libraries they were either heavy weight (5to6) or didn't have support for ...rest, shorthanding, and Source->Code->JSON

So I took some work on a basic Lambda expression parser I'd done in the past and expanded on it.

Install

npm install lambda-30
Testing

npm test
Usage

Basic

var L = require('lambda-30').Lambda;
var f = L('(a, b)=>a+b');
var val = f(5, 8);
// val is 13
f = L('$.a+$.b'); // No params supplied used $ as self reference
val = f({a: 3, b: 5});
// val is 8
Options

var Lambda = require('lambda-30').Lambda;
var L = new Lambda({selfSymbol: 'self'});
var f = L.compile('self.a+self.b');
var val = f({a: 3, b: 5});
// val is 8
Multi-line

var L = require('lambda-30').Lambda;
// note: long string form used for convience only
var f = L(`(a, b)=>{
    var c = 2;
    var sum = a+b;
    var avg = sum / c;
    return {
      count: c,
      sum: sum,
      avg: avg
    };
}`);
...rest

var L = require('lambda-30').Lambda;
// note: long string form used for convience only
var f = L(`(...nums)=>{
    var c = nums.length;
    var sum = nums.reduce(function(curr, next){
      return curr + next;
    }, 0);
    var avg = sum / c;
    return {
      count: c,
      sum: sum,
      avg: avg
    };
}`);
toJSON

Really this should be called toString but I didn't want to override the default toString implementation.

var L = require('lambda-30').Lambda;
var expected = '(a, b)=>{return a+b}';
var e = L(expected);
var js = e.toJSON();
assert(js===expected);

var e = Lambda(function($){
    return $.a+$.b;
  });
var s = e.toJSON();
var expected = '($)=>{\n        return $.a+$.b;\n      }';
assert(s===expected);