JS predicate combinator boilerplate. Riffing off Jack Firth's "Predicates in Javascript"

PredicateCombinators.js

// Firth: https://codepen.io/Universalist/post/predicates-in-javascript

(function(predicateCombinators) {
 
  // CPL predication
  
  function and(p1, p2) {
    return function(x) {
      return p1(x) && p2(x);
    }
  }
  
  function or(p1, p2) {
    return function(x) {
      return p1(x) || p2(x);
    }
  }
  
  function not(p) {
    return function(x) {
      return !p(x);
    }
  }
  
  function nor(p1, p2) {
    return function(x) {
      return !p1(x) && !p2(x);
    }
  }
  
  function nand(p1, p2) {
    return function(x) {
      return !(p1(x) && p2(x)) && (p1(x) || p2(x));
    }
  }

  // Positive and negative
  
  function positive(x) {
      return x > 0;
  }
  
  function negative(x) {
    return x < 0;
  }
  
  var nonzero = or(negative, positive);
    
  // Inequalities
  
  function greater(x) {
    return function(y) {
      return y > x;
    }
  }
  
  function less(x) {
    return function(y) {
      return y < x;
    }
  }
  
  function equal(x) {
    return function(y) {
      return y === x;
    }
  }
  
  // Kinds of numbers
  
  function natural(x) {
    return x >= 1;
  }
  
  function whole(x) {
    return x >= 0;
  }
  
  function int(x) {
    return x === Math.round(x);
  }
  
}());