lodash/lodash._basecallback/index.js

/**
 * lodash 3.1.3 (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 1.8.2 <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'),
    keys = require('lodash.keys');

/**
 * 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 typeof thisArg == 'undefined'
      ? func
      : bindCallback(func, thisArg, argCount);
  }
  if (func == null) {
    return identity;
  }
  if (type == 'object') {
    return baseMatches(func);
  }
  return typeof thisArg == 'undefined'
    ? baseProperty(func + '')
    : baseMatchesProperty(func + '', thisArg);
}

/**
 * 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 = typeof objValue != 'undefined' || (key in object);
    } else {
      result = customizer ? customizer(objValue, srcValue, key) : undefined;
      if (typeof 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) {
        return object != null && object[key] === value &&
          (typeof 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 coerce `key`
 * to a string.
 *
 * @private
 * @param {string} key The key of the property to get.
 * @param {*} value The value to compare.
 * @returns {Function} Returns the new function.
 */
function baseMatchesProperty(key, value) {
  if (isStrictComparable(value)) {
    return function(object) {
      return object != null && object[key] === value &&
        (typeof value != 'undefined' || (key in toObject(object)));
    };
  }
  return function(object) {
    return object != null && baseIsEqual(value, object[key], null, true);
  };
}

/**
 * The base implementation of `_.property` which does not coerce `key` to a string.
 *
 * @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];
  };
}

/**
 * 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 && (value === 0 ? ((1 / value) > 0) : !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);
}

/**
 * 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;
}

module.exports = baseCallback;