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Bump to v4.11.0.
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John-David Dalton
295
lodash.nth/index.js
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295
lodash.nth/index.js
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/**
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* lodash 4.11.0 (Custom Build) <https://lodash.com/>
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* Build: `lodash modularize exports="npm" -o ./`
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* Copyright jQuery Foundation and other contributors <https://jquery.org/>
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* Released under MIT license <https://lodash.com/license>
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* Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
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* Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
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*/
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/** Used as references for various `Number` constants. */
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var INFINITY = 1 / 0,
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MAX_SAFE_INTEGER = 9007199254740991,
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MAX_INTEGER = 1.7976931348623157e+308,
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NAN = 0 / 0;
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/** `Object#toString` result references. */
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var funcTag = '[object Function]',
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genTag = '[object GeneratorFunction]',
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symbolTag = '[object Symbol]';
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/** Used to match leading and trailing whitespace. */
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var reTrim = /^\s+|\s+$/g;
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/** Used to detect bad signed hexadecimal string values. */
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var reIsBadHex = /^[-+]0x[0-9a-f]+$/i;
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/** Used to detect binary string values. */
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var reIsBinary = /^0b[01]+$/i;
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/** Used to detect octal string values. */
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var reIsOctal = /^0o[0-7]+$/i;
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/** Used to detect unsigned integer values. */
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var reIsUint = /^(?:0|[1-9]\d*)$/;
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/** Built-in method references without a dependency on `root`. */
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var freeParseInt = parseInt;
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/**
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* Checks if `value` is a valid array-like index.
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*
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* @private
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* @param {*} value The value to check.
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* @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
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* @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
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*/
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function isIndex(value, length) {
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value = (typeof value == 'number' || reIsUint.test(value)) ? +value : -1;
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length = length == null ? MAX_SAFE_INTEGER : length;
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return value > -1 && value % 1 == 0 && value < length;
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}
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/** Used for built-in method references. */
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var objectProto = Object.prototype;
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/**
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* Used to resolve the
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* [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
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* of values.
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*/
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var objectToString = objectProto.toString;
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/**
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* The base implementation of `_.nth` which doesn't coerce `n` to an integer.
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*
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* @private
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* @param {Array} array The array to query.
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* @param {number} n The index of the element to return.
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* @returns {*} Returns the nth element of `array`.
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*/
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function baseNth(array, n) {
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var length = array.length;
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if (!length) {
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return;
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}
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n += n < 0 ? length : 0;
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return isIndex(n, length) ? array[n] : undefined;
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}
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/**
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* Gets the nth element of `array`. If `n` is negative, the nth element
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* from the end is returned.
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*
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* @static
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* @memberOf _
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* @since 4.11.0
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* @category Array
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* @param {Array} array The array to query.
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* @param {number} [n=0] The index of the element to return.
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* @returns {*} Returns the nth element of `array`.
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* @example
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*
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* var array = ['a', 'b', 'c', 'd'];
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*
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* _.nth(array, 1);
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* // => 'b'
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*
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* _.nth(array, -2);
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* // => 'c';
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*/
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function nth(array, n) {
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return (array && array.length) ? baseNth(array, toInteger(n)) : undefined;
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}
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/**
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* Checks if `value` is classified as a `Function` object.
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*
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* @static
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* @memberOf _
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* @since 0.1.0
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* @category Lang
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* @param {*} value The value to check.
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* @returns {boolean} Returns `true` if `value` is correctly classified,
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* else `false`.
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* @example
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*
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* _.isFunction(_);
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* // => true
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*
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* _.isFunction(/abc/);
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* // => false
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*/
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function isFunction(value) {
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// The use of `Object#toString` avoids issues with the `typeof` operator
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// in Safari 8 which returns 'object' for typed array and weak map constructors,
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// and PhantomJS 1.9 which returns 'function' for `NodeList` instances.
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var tag = isObject(value) ? objectToString.call(value) : '';
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return tag == funcTag || tag == genTag;
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}
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/**
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* Checks if `value` is the
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* [language type](http://www.ecma-international.org/ecma-262/6.0/#sec-ecmascript-language-types)
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* of `Object`. (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
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*
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* @static
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* @memberOf _
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* @since 0.1.0
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* @category Lang
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* @param {*} value The value to check.
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* @returns {boolean} Returns `true` if `value` is an object, else `false`.
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* @example
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*
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* _.isObject({});
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* // => true
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*
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* _.isObject([1, 2, 3]);
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* // => true
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*
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* _.isObject(_.noop);
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* // => true
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*
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* _.isObject(null);
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* // => false
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*/
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function isObject(value) {
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var type = typeof value;
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return !!value && (type == 'object' || type == 'function');
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}
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/**
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* Checks if `value` is object-like. A value is object-like if it's not `null`
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* and has a `typeof` result of "object".
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*
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* @static
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* @memberOf _
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* @since 4.0.0
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* @category Lang
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* @param {*} value The value to check.
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* @returns {boolean} Returns `true` if `value` is object-like, else `false`.
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* @example
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*
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* _.isObjectLike({});
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* // => true
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*
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* _.isObjectLike([1, 2, 3]);
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* // => true
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*
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* _.isObjectLike(_.noop);
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* // => false
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*
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* _.isObjectLike(null);
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* // => false
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*/
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function isObjectLike(value) {
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return !!value && typeof value == 'object';
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}
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/**
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* Checks if `value` is classified as a `Symbol` primitive or object.
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*
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* @static
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* @memberOf _
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* @since 4.0.0
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* @category Lang
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* @param {*} value The value to check.
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* @returns {boolean} Returns `true` if `value` is correctly classified,
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* else `false`.
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* @example
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*
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* _.isSymbol(Symbol.iterator);
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* // => true
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*
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* _.isSymbol('abc');
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* // => false
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*/
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function isSymbol(value) {
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return typeof value == 'symbol' ||
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(isObjectLike(value) && objectToString.call(value) == symbolTag);
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}
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/**
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* Converts `value` to an integer.
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*
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* **Note:** This function is loosely based on
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* [`ToInteger`](http://www.ecma-international.org/ecma-262/6.0/#sec-tointeger).
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*
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* @static
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* @memberOf _
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* @since 4.0.0
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* @category Lang
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* @param {*} value The value to convert.
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* @returns {number} Returns the converted integer.
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* @example
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*
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* _.toInteger(3);
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* // => 3
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*
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* _.toInteger(Number.MIN_VALUE);
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* // => 0
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*
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* _.toInteger(Infinity);
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* // => 1.7976931348623157e+308
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*
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* _.toInteger('3');
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* // => 3
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*/
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function toInteger(value) {
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if (!value) {
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return value === 0 ? value : 0;
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}
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value = toNumber(value);
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if (value === INFINITY || value === -INFINITY) {
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var sign = (value < 0 ? -1 : 1);
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return sign * MAX_INTEGER;
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}
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var remainder = value % 1;
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return value === value ? (remainder ? value - remainder : value) : 0;
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}
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/**
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* Converts `value` to a number.
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*
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* @static
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* @memberOf _
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* @since 4.0.0
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* @category Lang
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* @param {*} value The value to process.
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* @returns {number} Returns the number.
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* @example
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*
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* _.toNumber(3);
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* // => 3
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*
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* _.toNumber(Number.MIN_VALUE);
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* // => 5e-324
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*
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* _.toNumber(Infinity);
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* // => Infinity
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*
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* _.toNumber('3');
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* // => 3
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*/
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function toNumber(value) {
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if (typeof value == 'number') {
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return value;
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}
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if (isSymbol(value)) {
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return NAN;
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}
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if (isObject(value)) {
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var other = isFunction(value.valueOf) ? value.valueOf() : value;
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value = isObject(other) ? (other + '') : other;
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}
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if (typeof value != 'string') {
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return value === 0 ? value : +value;
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}
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value = value.replace(reTrim, '');
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var isBinary = reIsBinary.test(value);
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return (isBinary || reIsOctal.test(value))
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? freeParseInt(value.slice(2), isBinary ? 2 : 8)
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: (reIsBadHex.test(value) ? NAN : +value);
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}
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module.exports = nth;
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