lodash-es/isNumber.js

import isObjectLike from './isObjectLike';

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

/** 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;

/**
 * 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 _
 * @since 0.1.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is correctly classified,
 *  else `false`.
 * @example
 *
 * _.isNumber(3);
 * // => true
 *
 * _.isNumber(Number.MIN_VALUE);
 * // => true
 *
 * _.isNumber(Infinity);
 * // => true
 *
 * _.isNumber('3');
 * // => false
 */
function isNumber(value) {
  return typeof value == 'number' ||
    (isObjectLike(value) && objectToString.call(value) == numberTag);
}

export default isNumber;