lodash/lodash._basecallback/index.js

/**
 * lodash 3.2.1 (Custom Build) <https://lodash.com/>
 * Build: `lodash modern modularize exports="npm" -o ./`
 * Copyright 2012-2015 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <https://lodash.com/license>
 */
var baseIsEqual = require('lodash._baseisequal'),
    bindCallback = require('lodash._bindcallback'),
    isArray = require('lodash.isarray'),
    keys = require('lodash.keys');

/** Used to match property names within property paths. */
var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\n\\]|\\.)*?\1)\]/,
    reIsPlainProp = /^\w*$/,
    rePropName = /[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\n\\]|\\.)*?)\2)\]/g;

/** Used to match backslashes in property paths. */
var reEscapeChar = /\\(\\)?/g;

/**
 * Converts `value` to a string if it is not one. An empty string is returned
 * for `null` or `undefined` values.
 *
 * @private
 * @param {*} value The value to process.
 * @returns {string} Returns the string.
 */
function baseToString(value) {
  if (typeof value == 'string') {
    return value;
  }
  return value == null ? '' : (value + '');
}

/**
 * The base implementation of `_.callback` which supports specifying the
 * number of arguments to provide to `func`.
 *
 * @private
 * @param {*} [func=_.identity] The value to convert to a callback.
 * @param {*} [thisArg] The `this` binding of `func`.
 * @param {number} [argCount] The number of arguments to provide to `func`.
 * @returns {Function} Returns the callback.
 */
function baseCallback(func, thisArg, argCount) {
  var type = typeof func;
  if (type == 'function') {
    return thisArg === undefined
      ? func
      : bindCallback(func, thisArg, argCount);
  }
  if (func == null) {
    return identity;
  }
  if (type == 'object') {
    return baseMatches(func);
  }
  return thisArg === undefined
    ? property(func)
    : baseMatchesProperty(func, thisArg);
}

/**
 * The base implementation of `get` without support for string paths
 * and default values.
 *
 * @private
 * @param {Object} object The object to query.
 * @param {Array} path The path of the property to get.
 * @param {string} [pathKey] The key representation of path.
 * @returns {*} Returns the resolved value.
 */
function baseGet(object, path, pathKey) {
  if (object == null) {
    return;
  }
  if (pathKey !== undefined && pathKey in toObject(object)) {
    path = [pathKey];
  }
  var index = -1,
      length = path.length;

  while (object != null && ++index < length) {
    object = object[path[index]];
  }
  return (index && index == length) ? object : undefined;
}

/**
 * The base implementation of `_.isMatch` without support for callback
 * shorthands and `this` binding.
 *
 * @private
 * @param {Object} object The object to inspect.
 * @param {Array} props The source property names to match.
 * @param {Array} values The source values to match.
 * @param {Array} strictCompareFlags Strict comparison flags for source values.
 * @param {Function} [customizer] The function to customize comparing objects.
 * @returns {boolean} Returns `true` if `object` is a match, else `false`.
 */
function baseIsMatch(object, props, values, strictCompareFlags, customizer) {
  var index = -1,
      length = props.length,
      noCustomizer = !customizer;

  while (++index < length) {
    if ((noCustomizer && strictCompareFlags[index])
          ? values[index] !== object[props[index]]
          : !(props[index] in object)
        ) {
      return false;
    }
  }
  index = -1;
  while (++index < length) {
    var key = props[index],
        objValue = object[key],
        srcValue = values[index];

    if (noCustomizer && strictCompareFlags[index]) {
      var result = objValue !== undefined || (key in object);
    } else {
      result = customizer ? customizer(objValue, srcValue, key) : undefined;
      if (result === undefined) {
        result = baseIsEqual(srcValue, objValue, customizer, true);
      }
    }
    if (!result) {
      return false;
    }
  }
  return true;
}

/**
 * The base implementation of `_.matches` which does not clone `source`.
 *
 * @private
 * @param {Object} source The object of property values to match.
 * @returns {Function} Returns the new function.
 */
function baseMatches(source) {
  var props = keys(source),
      length = props.length;

  if (!length) {
    return constant(true);
  }
  if (length == 1) {
    var key = props[0],
        value = source[key];

    if (isStrictComparable(value)) {
      return function(object) {
        if (object == null) {
          return false;
        }
        return object[key] === value && (value !== undefined || (key in toObject(object)));
      };
    }
  }
  var values = Array(length),
      strictCompareFlags = Array(length);

  while (length--) {
    value = source[props[length]];
    values[length] = value;
    strictCompareFlags[length] = isStrictComparable(value);
  }
  return function(object) {
    return object != null && baseIsMatch(toObject(object), props, values, strictCompareFlags);
  };
}

/**
 * The base implementation of `_.matchesProperty` which does not which does
 * not clone `value`.
 *
 * @private
 * @param {string} path The path of the property to get.
 * @param {*} value The value to compare.
 * @returns {Function} Returns the new function.
 */
function baseMatchesProperty(path, value) {
  var isArr = isArray(path),
      isCommon = isKey(path) && isStrictComparable(value),
      pathKey = (path + '');

  path = toPath(path);
  return function(object) {
    if (object == null) {
      return false;
    }
    var key = pathKey;
    object = toObject(object);
    if ((isArr || !isCommon) && !(key in object)) {
      object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
      if (object == null) {
        return false;
      }
      key = last(path);
      object = toObject(object);
    }
    return object[key] === value
      ? (value !== undefined || (key in object))
      : baseIsEqual(value, object[key], null, true);
  };
}

/**
 * The base implementation of `_.property` without support for deep paths.
 *
 * @private
 * @param {string} key The key of the property to get.
 * @returns {Function} Returns the new function.
 */
function baseProperty(key) {
  return function(object) {
    return object == null ? undefined : object[key];
  };
}

/**
 * A specialized version of `baseProperty` which supports deep paths.
 *
 * @private
 * @param {Array|string} path The path of the property to get.
 * @returns {Function} Returns the new function.
 */
function basePropertyDeep(path) {
  var pathKey = (path + '');
  path = toPath(path);
  return function(object) {
    return baseGet(object, path, pathKey);
  };
}

/**
 * The base implementation of `_.slice` without an iteratee call guard.
 *
 * @private
 * @param {Array} array The array to slice.
 * @param {number} [start=0] The start position.
 * @param {number} [end=array.length] The end position.
 * @returns {Array} Returns the slice of `array`.
 */
function baseSlice(array, start, end) {
  var index = -1,
      length = array.length;

  start = start == null ? 0 : (+start || 0);
  if (start < 0) {
    start = -start > length ? 0 : (length + start);
  }
  end = (end === undefined || end > length) ? length : (+end || 0);
  if (end < 0) {
    end += length;
  }
  length = start > end ? 0 : ((end - start) >>> 0);
  start >>>= 0;

  var result = Array(length);
  while (++index < length) {
    result[index] = array[index + start];
  }
  return result;
}

/**
 * Checks if `value` is a property name and not a property path.
 *
 * @private
 * @param {*} value The value to check.
 * @param {Object} [object] The object to query keys on.
 * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
 */
function isKey(value, object) {
  var type = typeof value;
  if ((type == 'string' && reIsPlainProp.test(value)) || type == 'number') {
    return true;
  }
  if (isArray(value)) {
    return false;
  }
  var result = !reIsDeepProp.test(value);
  return result || (object != null && value in toObject(object));
}

/**
 * Checks if `value` is suitable for strict equality comparisons, i.e. `===`.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` if suitable for strict
 *  equality comparisons, else `false`.
 */
function isStrictComparable(value) {
  return value === value && !isObject(value);
}

/**
 * Converts `value` to an object if it is not one.
 *
 * @private
 * @param {*} value The value to process.
 * @returns {Object} Returns the object.
 */
function toObject(value) {
  return isObject(value) ? value : Object(value);
}

/**
 * Converts `value` to property path array if it is not one.
 *
 * @private
 * @param {*} value The value to process.
 * @returns {Array} Returns the property path array.
 */
function toPath(value) {
  if (isArray(value)) {
    return value;
  }
  var result = [];
  baseToString(value).replace(rePropName, function(match, number, quote, string) {
    result.push(quote ? string.replace(reEscapeChar, '$1') : (number || match));
  });
  return result;
}

/**
 * Gets the last element of `array`.
 *
 * @static
 * @memberOf _
 * @category Array
 * @param {Array} array The array to query.
 * @returns {*} Returns the last element of `array`.
 * @example
 *
 * _.last([1, 2, 3]);
 * // => 3
 */
function last(array) {
  var length = array ? array.length : 0;
  return length ? array[length - 1] : undefined;
}

/**
 * Checks if `value` is the [language type](https://es5.github.io/#x8) of `Object`.
 * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
 *
 * @static
 * @memberOf _
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is an object, else `false`.
 * @example
 *
 * _.isObject({});
 * // => true
 *
 * _.isObject([1, 2, 3]);
 * // => true
 *
 * _.isObject(1);
 * // => false
 */
function isObject(value) {
  // Avoid a V8 JIT bug in Chrome 19-20.
  // See https://code.google.com/p/v8/issues/detail?id=2291 for more details.
  var type = typeof value;
  return type == 'function' || (!!value && type == 'object');
}

/**
 * Creates a function that returns `value`.
 *
 * @static
 * @memberOf _
 * @category Utility
 * @param {*} value The value to return from the new function.
 * @returns {Function} Returns the new function.
 * @example
 *
 * var object = { 'user': 'fred' };
 * var getter = _.constant(object);
 *
 * getter() === object;
 * // => true
 */
function constant(value) {
  return function() {
    return value;
  };
}

/**
 * This method returns the first argument provided to it.
 *
 * @static
 * @memberOf _
 * @category Utility
 * @param {*} value Any value.
 * @returns {*} Returns `value`.
 * @example
 *
 * var object = { 'user': 'fred' };
 *
 * _.identity(object) === object;
 * // => true
 */
function identity(value) {
  return value;
}

/**
 * Creates a function which returns the property value at `path` on a
 * given object.
 *
 * @static
 * @memberOf _
 * @category Utility
 * @param {Array|string} path The path of the property to get.
 * @returns {Function} Returns the new function.
 * @example
 *
 * var objects = [
 *   { 'a': { 'b': { 'c': 2 } } },
 *   { 'a': { 'b': { 'c': 1 } } }
 * ];
 *
 * _.map(objects, _.property('a.b.c'));
 * // => [2, 1]
 *
 * _.pluck(_.sortBy(objects, _.property(['a', 'b', 'c'])), 'a.b.c');
 * // => [1, 2]
 */
function property(path) {
  return isKey(path) ? baseProperty(path) : basePropertyDeep(path);
}

module.exports = baseCallback;