lodash/lodash.isnumber/index.js

/**
 * lodash 3.0.0 (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 1.7.0 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <https://lodash.com/license>
 */

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

/**
 * Checks if `value` is object-like.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
 */
function isObjectLike(value) {
  return (value && typeof value == 'object') || false;
}

/** Used for native method references. */
var objectProto = Object.prototype;

/**
 * Used to resolve the `toStringTag` of values.
 * See the [ES spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
 * for more details.
 */
var objToString = objectProto.toString;

/**
 * Checks if `value` is classified as a `Number` primitive or object.
 *
 * **Note:** To exclude `Infinity`, `-Infinity`, and `NaN`, which are classified
 * as numbers, use the `_.isFinite` method.
 *
 * @static
 * @memberOf _
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
 * @example
 *
 * _.isNumber(8.4);
 * // => true
 *
 * _.isNumber(NaN);
 * // => true
 *
 * _.isNumber('8.4');
 * // => false
 */
function isNumber(value) {
  return typeof value == 'number' || (isObjectLike(value) && objToString.call(value) == numberTag) || false;
}

module.exports = isNumber;