streaming-max.js

//     wink-statistics
//     Fast and Numerically Stable Statistical Analysis Utilities.
//
//     Copyright (C) 2017-18  GRAYPE Systems Private Limited
//
//     This file is part of “wink-statistics”.
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// ## streaming

// ### max
/**
 *
 * Maximum value is determined incrementally with arrival of each value from the data stream.
 *
 * The [`compute()`](http://winkjs.org/wink-statistics/Stream.html#compute) requires
 * a single numeric value as argument.
 *
 * The [`result()`](http://winkjs.org/wink-statistics/Stream.html#result) returns
 * an object containing `max`.
 *
 * @memberof streaming#
 * @return {Stream} Object containing methods such as `compute()`, `result()` & `reset()`.
 * @example
 * var maximum = max();
 * maximum.compute( 3 );
 * maximum.compute( 6 );
 * maximum.value();
 * // returns 6
 * maximum.result();
 * // returns { max: 6 }
 */
var max = function () {
  var maximum = -Infinity;
  var methods = Object.create( null );

  methods.compute = function ( di ) {
    maximum = ( maximum < di ) ? di : maximum;
    return undefined;
  }; // compute()

  methods.value = function () {
    return maximum;
  }; // value()

  methods.result = function () {
    var obj = Object.create( null );
    obj.max = maximum;
    return obj;
  }; // result()

  methods.reset = function () {
    maximum = -Infinity;
  }; // reset()

  return methods;
}; // max()

module.exports = max;