lodash/lodash._baseintersection/index.js

/**
 * lodash 4.4.1 (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright 2012-2016 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2016 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <https://lodash.com/license>
 */
var SetCache = require('lodash._setcache');

/** Used to stand-in for `undefined` hash values. */
var HASH_UNDEFINED = '__lodash_hash_undefined__';

/**
 * A specialized version of `_.includes` for arrays without support for
 * specifying an index to search from.
 *
 * @private
 * @param {Array} array The array to search.
 * @param {*} target The value to search for.
 * @returns {boolean} Returns `true` if `target` is found, else `false`.
 */
function arrayIncludes(array, value) {
  return !!array.length && baseIndexOf(array, value, 0) > -1;
}

/**
 * This function is like `arrayIncludes` except that it accepts a comparator.
 *
 * @private
 * @param {Array} array The array to search.
 * @param {*} target The value to search for.
 * @param {Function} comparator The comparator invoked per element.
 * @returns {boolean} Returns `true` if `target` is found, else `false`.
 */
function arrayIncludesWith(array, value, comparator) {
  var index = -1,
      length = array.length;

  while (++index < length) {
    if (comparator(value, array[index])) {
      return true;
    }
  }
  return false;
}

/**
 * A specialized version of `_.map` for arrays without support for iteratee
 * shorthands.
 *
 * @private
 * @param {Array} array The array to iterate over.
 * @param {Function} iteratee The function invoked per iteration.
 * @returns {Array} Returns the new mapped array.
 */
function arrayMap(array, iteratee) {
  var index = -1,
      length = array.length,
      result = Array(length);

  while (++index < length) {
    result[index] = iteratee(array[index], index, array);
  }
  return result;
}

/**
 * The base implementation of `_.indexOf` without `fromIndex` bounds checks.
 *
 * @private
 * @param {Array} array The array to search.
 * @param {*} value The value to search for.
 * @param {number} fromIndex The index to search from.
 * @returns {number} Returns the index of the matched value, else `-1`.
 */
function baseIndexOf(array, value, fromIndex) {
  if (value !== value) {
    return indexOfNaN(array, fromIndex);
  }
  var index = fromIndex - 1,
      length = array.length;

  while (++index < length) {
    if (array[index] === value) {
      return index;
    }
  }
  return -1;
}

/**
 * The base implementation of `_.unary` without support for storing wrapper metadata.
 *
 * @private
 * @param {Function} func The function to cap arguments for.
 * @returns {Function} Returns the new function.
 */
function baseUnary(func) {
  return function(value) {
    return func(value);
  };
}

/**
 * Gets the index at which the first occurrence of `NaN` is found in `array`.
 *
 * @private
 * @param {Array} array The array to search.
 * @param {number} fromIndex The index to search from.
 * @param {boolean} [fromRight] Specify iterating from right to left.
 * @returns {number} Returns the index of the matched `NaN`, else `-1`.
 */
function indexOfNaN(array, fromIndex, fromRight) {
  var length = array.length,
      index = fromIndex + (fromRight ? 0 : -1);

  while ((fromRight ? index-- : ++index < length)) {
    var other = array[index];
    if (other !== other) {
      return index;
    }
  }
  return -1;
}

/* Built-in method references for those with the same name as other `lodash` methods. */
var nativeMin = Math.min;

/**
 * Checks if `value` is in `cache`.
 *
 * @private
 * @param {Object} cache The set cache to search.
 * @param {*} value The value to search for.
 * @returns {number} Returns `true` if `value` is found, else `false`.
 */
function cacheHas(cache, value) {
  var map = cache.__data__;
  if (isKeyable(value)) {
    var data = map.__data__,
        hash = typeof value == 'string' ? data.string : data.hash;

    return hash[value] === HASH_UNDEFINED;
  }
  return map.has(value);
}

/**
 * The base implementation of methods like `_.intersection`, without support
 * for iteratee shorthands, that accepts an array of arrays to inspect.
 *
 * @private
 * @param {Array} arrays The arrays to inspect.
 * @param {Function} [iteratee] The iteratee invoked per element.
 * @param {Function} [comparator] The comparator invoked per element.
 * @returns {Array} Returns the new array of shared values.
 */
function baseIntersection(arrays, iteratee, comparator) {
  var includes = comparator ? arrayIncludesWith : arrayIncludes,
      length = arrays[0].length,
      othLength = arrays.length,
      othIndex = othLength,
      caches = Array(othLength),
      maxLength = Infinity,
      result = [];

  while (othIndex--) {
    var array = arrays[othIndex];
    if (othIndex && iteratee) {
      array = arrayMap(array, baseUnary(iteratee));
    }
    maxLength = nativeMin(array.length, maxLength);
    caches[othIndex] = !comparator && (iteratee || (length >= 120 && array.length >= 120))
      ? new SetCache(othIndex && array)
      : undefined;
  }
  array = arrays[0];

  var index = -1,
      seen = caches[0];

  outer:
  while (++index < length && result.length < maxLength) {
    var value = array[index],
        computed = iteratee ? iteratee(value) : value;

    if (!(seen
          ? cacheHas(seen, computed)
          : includes(result, computed, comparator)
        )) {
      othIndex = othLength;
      while (--othIndex) {
        var cache = caches[othIndex];
        if (!(cache
              ? cacheHas(cache, computed)
              : includes(arrays[othIndex], computed, comparator))
            ) {
          continue outer;
        }
      }
      if (seen) {
        seen.push(computed);
      }
      result.push(value);
    }
  }
  return result;
}

/**
 * Checks if `value` is suitable for use as unique object key.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is suitable, else `false`.
 */
function isKeyable(value) {
  var type = typeof value;
  return type == 'number' || type == 'boolean' ||
    (type == 'string' && value != '__proto__') || value == null;
}

module.exports = baseIntersection;