lodash/lodash.sortedindex/index.js

/**
 * lodash (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright jQuery Foundation and other contributors <https://jquery.org/>
 * Released under MIT license <https://lodash.com/license>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 */

/** Used as references for the maximum length and index of an array. */
var MAX_ARRAY_LENGTH = 4294967295,
    MAX_ARRAY_INDEX = MAX_ARRAY_LENGTH - 1,
    HALF_MAX_ARRAY_LENGTH = MAX_ARRAY_LENGTH >>> 1;

/** `Object#toString` result references. */
var symbolTag = '[object Symbol]';

/** Used for built-in method references. */
var objectProto = Object.prototype;

/**
 * Used to resolve the
 * [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
 * of values.
 */
var objectToString = objectProto.toString;

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

/**
 * The base implementation of `_.sortedIndex` and `_.sortedLastIndex` which
 * performs a binary search of `array` to determine the index at which `value`
 * should be inserted into `array` in order to maintain its sort order.
 *
 * @private
 * @param {Array} array The sorted array to inspect.
 * @param {*} value The value to evaluate.
 * @param {boolean} [retHighest] Specify returning the highest qualified index.
 * @returns {number} Returns the index at which `value` should be inserted
 *  into `array`.
 */
function baseSortedIndex(array, value, retHighest) {
  var low = 0,
      high = array ? array.length : low;

  if (typeof value == 'number' && value === value && high <= HALF_MAX_ARRAY_LENGTH) {
    while (low < high) {
      var mid = (low + high) >>> 1,
          computed = array[mid];

      if (computed !== null && !isSymbol(computed) &&
          (retHighest ? (computed <= value) : (computed < value))) {
        low = mid + 1;
      } else {
        high = mid;
      }
    }
    return high;
  }
  return baseSortedIndexBy(array, value, identity, retHighest);
}

/**
 * The base implementation of `_.sortedIndexBy` and `_.sortedLastIndexBy`
 * which invokes `iteratee` for `value` and each element of `array` to compute
 * their sort ranking. The iteratee is invoked with one argument; (value).
 *
 * @private
 * @param {Array} array The sorted array to inspect.
 * @param {*} value The value to evaluate.
 * @param {Function} iteratee The iteratee invoked per element.
 * @param {boolean} [retHighest] Specify returning the highest qualified index.
 * @returns {number} Returns the index at which `value` should be inserted
 *  into `array`.
 */
function baseSortedIndexBy(array, value, iteratee, retHighest) {
  value = iteratee(value);

  var low = 0,
      high = array ? array.length : 0,
      valIsNaN = value !== value,
      valIsNull = value === null,
      valIsSymbol = isSymbol(value),
      valIsUndefined = value === undefined;

  while (low < high) {
    var mid = nativeFloor((low + high) / 2),
        computed = iteratee(array[mid]),
        othIsDefined = computed !== undefined,
        othIsNull = computed === null,
        othIsReflexive = computed === computed,
        othIsSymbol = isSymbol(computed);

    if (valIsNaN) {
      var setLow = retHighest || othIsReflexive;
    } else if (valIsUndefined) {
      setLow = othIsReflexive && (retHighest || othIsDefined);
    } else if (valIsNull) {
      setLow = othIsReflexive && othIsDefined && (retHighest || !othIsNull);
    } else if (valIsSymbol) {
      setLow = othIsReflexive && othIsDefined && !othIsNull && (retHighest || !othIsSymbol);
    } else if (othIsNull || othIsSymbol) {
      setLow = false;
    } else {
      setLow = retHighest ? (computed <= value) : (computed < value);
    }
    if (setLow) {
      low = mid + 1;
    } else {
      high = mid;
    }
  }
  return nativeMin(high, MAX_ARRAY_INDEX);
}

/**
 * Uses a binary search to determine the lowest index at which `value`
 * should be inserted into `array` in order to maintain its sort order.
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Array
 * @param {Array} array The sorted array to inspect.
 * @param {*} value The value to evaluate.
 * @returns {number} Returns the index at which `value` should be inserted
 *  into `array`.
 * @example
 *
 * _.sortedIndex([30, 50], 40);
 * // => 1
 */
function sortedIndex(array, value) {
  return baseSortedIndex(array, value);
}

/**
 * Checks if `value` is object-like. A value is object-like if it's not `null`
 * and has a `typeof` result of "object".
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
 * @example
 *
 * _.isObjectLike({});
 * // => true
 *
 * _.isObjectLike([1, 2, 3]);
 * // => true
 *
 * _.isObjectLike(_.noop);
 * // => false
 *
 * _.isObjectLike(null);
 * // => false
 */
function isObjectLike(value) {
  return !!value && typeof value == 'object';
}

/**
 * Checks if `value` is classified as a `Symbol` primitive or object.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a symbol, else `false`.
 * @example
 *
 * _.isSymbol(Symbol.iterator);
 * // => true
 *
 * _.isSymbol('abc');
 * // => false
 */
function isSymbol(value) {
  return typeof value == 'symbol' ||
    (isObjectLike(value) && objectToString.call(value) == symbolTag);
}

/**
 * This method returns the first argument it receives.
 *
 * @static
 * @since 0.1.0
 * @memberOf _
 * @category Util
 * @param {*} value Any value.
 * @returns {*} Returns `value`.
 * @example
 *
 * var object = { 'a': 1 };
 *
 * console.log(_.identity(object) === object);
 * // => true
 */
function identity(value) {
  return value;
}

module.exports = sortedIndex;