lambdax

lambdax is an small module that allows you to implement partial application and build lambda expressions.

Install

• npm

npm install --save lambdax

• bower

bower install --save lambdax

Usage

lambdax exposes two functions: partial() and negate();

var partial = require('../lambdax').partial;
var negate = require('../lambdax').negate;

partial()

• partial() simple use:

function sum(a, b, c) {
  return a + b + c;
}
var sumPlus15 = partial(sum, 15);
sumPlus15(25, 20); // => 60

• partial() simple use passing context and arguments:

 
function getColeguesNamesFromPeople(people) {
  var _self = this;
  return people.reduce(function (colegues, person) {
    if (person.occupation === _self.occupation) {
      colegues.push(person.firstName);
    }
 
    return colegues;
  }, []);
}
 
var getJohnColeguesNamesFromPeople = partial(
  john, // context
  getJohnColeguesNamesFromPeople,
);
 
getJohnColeguesNamesFromPeople(people);

• partial() use as a builder:

var findBackendDeveloper = partial()
  .expression(function () {
    return this.reduce(function (backendDevelopers, person) {
      if (person.occupation === 'Backend Developer') {
        backendDevelopers.push(person);
      }
 
      return backendDevelopers;
    }, []);
  })
  .context(people)
  .build();
 
findBackendDeveloper();

negate()

• negate() simple use

var f = negate(function () { return true });
f() // => false.

• negate() simple use passing context and arguments:

var minAge = 18;
var maxAge = 30;
var isAgeNotInRange = negate(
  john, // context
  function (minAge, maxAge) {
    return this.age >= minAge && this.age <= maxAge;
  },
  minAge
  // we could've passed maxAge too,
  // but we didn't just to demonstrate that can pass it latter
);
 
isAgeNotInRange(maxAge);

• negate() use as a builder:

var isNotAgeInRange = negate()
  .expression(function (minAge, maxAge) {
    return this.age >= minAge && this.age <= maxAge;
  })
  .context(john)
  .argument(18)
  .argument(30)
  .build();
 
isNotAgeInRange();

Note: see test folder for more examples.