lodash/lodash.parseint/index.js

/**
 * lodash 3.2.0 (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 root = require('lodash._root');

/** Used as references for various `Number` constants. */
var INFINITY = 1 / 0;

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

/** Used to match leading and trailing whitespace. */
var reTrim = /^\s+|\s+$/g;

/** Used to detect hexadecimal string values. */
var reHasHexPrefix = /^0x/i;

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

/**
 * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
 * of values.
 */
var objectToString = objectProto.toString;

/** Built-in value references. */
var Symbol = root.Symbol;

/* Built-in method references for those with the same name as other `lodash` methods. */
var nativeParseInt = root.parseInt;

/** Used to convert symbols to primitives and strings. */
var symbolProto = Symbol ? Symbol.prototype : undefined,
    symbolToString = Symbol ? symbolProto.toString : undefined;

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

/**
 * Converts `value` to a string if it's not one. An empty string is returned
 * for `null` and `undefined` values. The sign of `-0` is preserved.
 *
 * @static
 * @memberOf _
 * @category Lang
 * @param {*} value The value to process.
 * @returns {string} Returns the string.
 * @example
 *
 * _.toString(null);
 * // => ''
 *
 * _.toString(-0);
 * // => '-0'
 *
 * _.toString([1, 2, 3]);
 * // => '1,2,3'
 */
function toString(value) {
  // Exit early for strings to avoid a performance hit in some environments.
  if (typeof value == 'string') {
    return value;
  }
  if (value == null) {
    return '';
  }
  if (isSymbol(value)) {
    return Symbol ? symbolToString.call(value) : '';
  }
  var result = (value + '');
  return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;
}

/**
 * Converts `string` to an integer of the specified radix. If `radix` is
 * `undefined` or `0`, a `radix` of `10` is used unless `value` is a hexadecimal,
 * in which case a `radix` of `16` is used.
 *
 * **Note:** This method aligns with the [ES5 implementation](https://es5.github.io/#x15.1.2.2)
 * of `parseInt`.
 *
 * @static
 * @memberOf _
 * @category String
 * @param {string} string The string to convert.
 * @param {number} [radix] The radix to interpret `value` by.
 * @param- {Object} [guard] Enables use as an iteratee for functions like `_.map`.
 * @returns {number} Returns the converted integer.
 * @example
 *
 * _.parseInt('08');
 * // => 8
 *
 * _.map(['6', '08', '10'], _.parseInt);
 * // => [6, 8, 10]
 */
function parseInt(string, radix, guard) {
  // Chrome fails to trim leading <BOM> whitespace characters.
  // See https://code.google.com/p/v8/issues/detail?id=3109 for more details.
  if (guard || radix == null) {
    radix = 0;
  } else if (radix) {
    radix = +radix;
  }
  string = toString(string).replace(reTrim, '');
  return nativeParseInt(string, radix || (reHasHexPrefix.test(string) ? 16 : 10));
}

module.exports = parseInt;