covutils/lib/range.js

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _slicedToArray = function () { function sliceIterator(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"]) _i["return"](); } finally { if (_d) throw _e; } } return _arr; } return function (arr, i) { if (Array.isArray(arr)) { return arr; } else if (Symbol.iterator in Object(arr)) { return sliceIterator(arr, i); } else { throw new TypeError("Invalid attempt to destructure non-iterable instance"); } }; }();

exports.minMaxOfRange = minMaxOfRange;
exports.reduceRange = reduceRange;
exports.iterateRange = iterateRange;

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }

/**
 * @external {Range} https://github.com/Reading-eScience-Centre/coverage-jsapi/blob/master/Range.md
 */

/**
 * Return the minimum/maximum across all range values, ignoring null's.
 *
 * @param {Range<number>} range The numeric coverage data range.
 * @return {[min,max]} The minimum and maximum values of the range,
 *   or [undefined, undefined] if the range contains only `null` values.
 */
function minMaxOfRange(range) {
  var min = Infinity;
  var max = -Infinity;
  var fn = function fn(val) {
    if (val === null) return;
    if (val < min) min = val;
    if (val > max) max = val;
  };
  iterateRange(range, fn);
  return min === Infinity ? [undefined, undefined] : [min, max];
}

/**
 * Apply a reduce function over the range values.
 *
 * @param {Range} range The coverage data range.
 * @param {function} callback Function to execute on each value in the array with arguments `(previousValue, currentValue)`.
 * @param start Value to use as the first argument to the first call of the `callback`.
 * @return The reduced value.
 */
function reduceRange(range, callback, start) {
  var v1 = start;
  var iterFn = function iterFn(v2) {
    v1 = callback(v1, v2);
  };
  iterateRange(range, iterFn);
  return v1;
}

/**
 * Iterate over all range values and run a function for each value.
 * No particular iteration order must be assumed.
 */
function iterateRange(range, fn) {
  // We use a precompiled function here for efficiency.
  // See below for a slower recursive version.

  // Benchmarks compared to recursive version:
  // Chrome 46: around 1.03x faster
  // Firefox 42: around 2x faster (and around 6x faster than Chrome 46!)

  // nest loops from smallest to biggest
  var shape = [].concat(_toConsumableArray(range.shape));
  shape.sort(function (_ref, _ref2) {
    var _ref4 = _slicedToArray(_ref, 2);

    var size1 = _ref4[1];

    var _ref3 = _slicedToArray(_ref2, 2);

    var size2 = _ref3[1];
    return size1 - size2;
  });

  var begin = 'var obj = {}';
  var end = '';
  var _iteratorNormalCompletion = true;
  var _didIteratorError = false;
  var _iteratorError = undefined;

  try {
    for (var _iterator = shape[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
      var _step$value = _slicedToArray(_step.value, 2);

      var axis = _step$value[0];
      var size = _step$value[1];

      begin += '\n      for (var i' + axis + '=0; i' + axis + ' < ' + size + '; ++i' + axis + ') {\n        obj[\'' + axis + '\'] = i' + axis + '\n    ';
      end += '}';
    }
  } catch (err) {
    _didIteratorError = true;
    _iteratorError = err;
  } finally {
    try {
      if (!_iteratorNormalCompletion && _iterator.return) {
        _iterator.return();
      }
    } finally {
      if (_didIteratorError) {
        throw _iteratorError;
      }
    }
  }

  begin += '\n    fn(get(obj))\n  ';

  var iterateLoop = new Function('return function iterRange (get, fn) { ' + begin + ' ' + end + ' }')(); // eslint-disable-line
  iterateLoop(range.get, fn);
}

/*
 * Recursive version of iterate(). For reference only.
 *
export function iterate (range, fn) {
  let get = range.get
  let shape = [...range.shape]
  // iterate from smallest to biggest dimension
  shape.sort(([,size1], [,size2]) => size1 - size2)
  let dims = shape.length

  function iterateRecurse (obj, axisIdx) {
    if (dims === axisIdx) {
      fn(get(obj))
    } else {
      let [axis,size] = shape[axisIdx]
      for (let i=0; i < size; i++) {
        obj[axis] = i
        iterateRecurse(obj, axisIdx+1)
      }
    }
  }
  iterateRecurse({}, 0)
}
*/