johnny-five/lib/fn.js

The JavaScript Arduino Programming Framework.

var lodash = require("lodash"),
  Fn = {
    assign: lodash.assign,
    extend: lodash.extend,
    debounce: lodash.debounce,
    mixin: lodash.mixin
  };

// Fn.map( val, fromLow, fromHigh, toLow, toHigh )
//
// Re-maps a number from one range to another.
// Based on arduino map()
Fn.map = function(x, fromLow, fromHigh, toLow, toHigh) {
  return (x - fromLow) * (toHigh - toLow) /
    (fromHigh - fromLow) + toLow;
};

// Alias
Fn.scale = Fn.map;

// Fn.constrain( val, lower, upper )
//
// Constrains a number to be within a range.
// Based on arduino constrain()
Fn.constrain = function(x, lower, upper) {
  return x <= upper && x >= lower ? x :
    (x > upper ? upper : lower);
};

// Fn.range( upper )
// Fn.range( lower, upper )
// Fn.range( lower, upper, tick )
//
// Returns a new array range
//
Fn.range = function(lower, upper, tick) {

  if (arguments.length === 1) {
    upper = lower;
    lower = 0;
  }

  lower = lower || 0;
  upper = upper || 0;
  tick = tick || 1;

  var len = Math.max(Math.ceil((upper - lower) / tick), 0),
    idx = 0,
    range = [];

  while (idx <= len) {
    range[idx++] = lower;
    lower += tick;
  }

  return range;
};

// Fn.range.prefixed( prefix, upper )
// Fn.range.prefixed( prefix, lower, upper )
// Fn.range.prefixed( prefix, lower, upper, tick )
//
// Returns a new array range, each value prefixed
//
Fn.range.prefixed = function(prefix, lower, upper, tick) {
  return Fn.range.apply(null, [].slice.call(arguments, 1)).map(function(val) {
    return prefix + val;
  });
};

// Fn.uid()
//
// Returns a reasonably unique id string
//
Fn.uid = function() {
  return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, function(chr) {
    var rnd = Math.random() * 16 | 0;
    return (chr === "x" ? rnd : (rnd & 0x3 | 0x8)).toString(16);
  }).toUpperCase();
};

// Fn.square()
//
// Returns squared x
//
Fn.square = function(x) {
  return x * x;
};

// Fn.sleep( ms )
//  delay for ms
//
// Returns undefined
//
Fn.sleep = function(ms) {
  var start = Date.now();
  while (Date.now() < start + ms) {}
};


Fn.sum = function sum(values) {
  return values.reduce(function(accum, value) {
    return accum + value;
  }, 0);
};



module.exports = Fn;