util.js

/*
 * Returns the smallest value in the array.
 */
exports.min = function(values) {
  return Math.min.apply(null, values);
};

/*
 * Returns the largest value in the array.
 */
exports.max = function(values) {
  return Math.max.apply(null, values);
};

/*
 * Returns `true` only if `f(x)` is `true` for all `x` in `xs`. Otherwise
 * returns `false`. This function will return immediately if it finds a
 * case where `f(x)` does not hold.
 */
exports.all = function(xs, f) {
  for (var i = 0; i < xs.length; ++i) {
    if (!f(xs[i])) {
      return false;
    }
  }
  return true;
};

/*
 * Accumulates the sum of elements in the given array using the `+` operator.
 */
exports.sum = function(values) {
  return values.reduce(function(acc, x) { return acc + x; }, 0);
};

/*
 * Returns an array of all values in the given object.
 */
exports.values = function(obj) {
  return Object.keys(obj).map(function(k) { return obj[k]; });
};

exports.createTimer = function(enabled) {
  var self = {};

  // Default to disabled
  enabled = enabled || false;

  self.enabled = function(x) {
    if (!arguments.length) return enabled;
    enabled = x;
    return self;
  };

  self.wrap = function(name, func) {
    return function() {
      var start = enabled ? new Date().getTime() : null;
      try {
        return func.apply(null, arguments);
      } finally {
        if (start) console.log(name + " time: " + (new Date().getTime() - start) + "ms");
      }
    };
  };

  return self;
};

exports.propertyAccessor = function(self, config, field, setHook) {
  return function(x) {
    if (!arguments.length) return config[field];
    config[field] = x;
    if (setHook) setHook(x);
    return self;
  };
};