@instructure/quiz-interactions/es/util/combinatorics.js

A React UI component Library for quiz interaction types.

import _toConsumableArray from "@babel/runtime/helpers/esm/toConsumableArray";
import _slicedToArray from "@babel/runtime/helpers/esm/slicedToArray";
import times from 'lodash/fp/times';
import concat from 'lodash/fp/concat';
import map from 'lodash/fp/map';
import reduce from 'lodash/fp/reduce';
import range from 'lodash/fp/range';
import flatten from 'lodash/fp/flatten';
export function identityMatrix(_ref, size) {
  var _ref2 = _slicedToArray(_ref, 2),
    _ref2$ = _ref2[0],
    a = _ref2$ === void 0 ? 1 : _ref2$,
    _ref2$2 = _ref2[1],
    b = _ref2$2 === void 0 ? 0 : _ref2$2;
  return map(function (row) {
    return times(function (n) {
      return n === row ? a : b;
    }, size);
  }, range(0, size));
}

// same concept as https://github.com/dankogai/js-combinatorics#cartesian-product
export function cartesianProduct() {
  for (var _len = arguments.length, arrays = new Array(_len), _key = 0; _key < _len; _key++) {
    arrays[_key] = arguments[_key];
  }
  return reduce(function (a, b) {
    return flatten(map(function (x) {
      return map(function (y) {
        return concat(x, [y]);
      }, b);
    }, a));
  }, [[]], arrays);
}

// same concept as https://github.com/dankogai/js-combinatorics#base-n
export function baseNCombination(values, n) {
  if (n === 0) {
    return [];
  }
  if (n === 1) {
    return map(function (v) {
      return [v];
    }, values);
  }
  var previous = baseNCombination(values, n - 1);
  return cartesianProduct(values, previous).map(function (_ref3) {
    var _ref4 = _slicedToArray(_ref3, 2),
      v = _ref4[0],
      p = _ref4[1];
    return [v].concat(_toConsumableArray(p));
  });
}

// same concept as https://github.com/dankogai/js-combinatorics#combination
export function combination(array, size) {
  if (size === 0) {
    return [];
  }
  if (size === 1) {
    return map(function (v) {
      return [v];
    }, array);
  }
  if (array.length === 1) {
    return [times(function () {
      return array[0];
    }, size)];
  }
  if (array.length === 0) {
    return [];
  }
  return concat(map(function (v) {
    return [array[0]].concat(_toConsumableArray(v));
  }, combination(array, size - 1)), combination(array.slice(1), size));
}