u3 - Utility Functions

This lib contains utility functions for e3, dataflower and other projects.

Documentation

Installation

npm install u3

bower install u3

Usage

In this documentation I used the lib as follows:

var u3 = require("u3"),
    cache = u3.cache,
    eachCombination = u3.eachCombination;

Function wrappers

cache

The cache(fn) function caches the fn results, so by the next calls it will return the result of the first call. You can use different arguments, but they won't affect the return value.

var a = cache(function fn(x, y, z){
    return x + y + z;
});
console.log(a(1, 2, 3)); // 6
console.log(a()); // 6
console.log(a()); // 6

It is possible to cache a value too.

var a = cache(1 + 2 + 3);
console.log(a()); // 6
console.log(a()); // 6
console.log(a()); // 6

Math

eachCombination

The eachCombination(alternativesByDimension, callback) calls the callback(a,b,c,...) on each combination of the alternatives[a[],b[],c[],...].

eachCombination([
      [1, 2, 3],
      ["a", "b"]
  ], console.log);
  /*
      1, "a"
      1, "b"
      
      2, "a"
      2, "b"
      
      3, "a"
      3, "b"
  */

You can use any dimension and number of alternatives. In the current example we used 2 dimensions. By the first dimension we used 3 alternatives: [1, 2, 3] and by the second dimension we used 2 alternatives: ["a", "b"].

License

MIT - 2016 Jánszky László Lajos