/**
* Lodash (Custom Build) <https://lodash.com/>
* Build: `lodash modularize exports="npm" -o packages`
* Copyright OpenJS Foundation and other contributors <https://openjsf.org/>
* Released under MIT license <https://lodash.com/license>
* Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
* Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
*/
/** `Object#toString` result references. */
var argsTag = '[object Arguments]',
nullTag = '[object Null]',
undefinedTag = '[object Undefined]';
/** Detect free variable `global` from Node.js. */
var freeGlobal = typeof global == 'object' && global && global.Object === Object && global;
/** Detect free variable `globalThis` */
const freeGlobalThis = typeof globalThis == 'object' && globalThis !== null && globalThis.Object == Object && globalThis;
/** Detect free variable `self`. */
var freeSelf = typeof self == 'object' && self && self.Object === Object && self;
/** Used as a reference to the global object. */
var root = freeGlobalThis || freeGlobal || freeSelf || Function('return this')();
/**
* Appends the elements of `values` to `array`.
*
* @private
* @param {Array} array The array to modify.
* @param {Array} values The values to append.
* @returns {Array} Returns `array`.
*/
function arrayPush(array, values) {
var index = -1,
length = values.length,
offset = array.length;
while (++index < length) {
array[offset + index] = values[index];
}
return array;
}
/** Used for built-in method references. */
var objectProto = Object.prototype;
/** Used to check objects for own properties. */
var hasOwnProperty = objectProto.hasOwnProperty;
/**
* Used to resolve the
* [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
* of values.
*/
var nativeObjectToString = objectProto.toString;
/** Built-in value references. */
var Symbol = root.Symbol,
propertyIsEnumerable = objectProto.propertyIsEnumerable,
spreadableSymbol = Symbol ? Symbol.isConcatSpreadable : undefined,
symToStringTag = Symbol ? Symbol.toStringTag : undefined;
/**
* The base implementation of `_.flatten` with support for restricting flattening.
*
* @private
* @param {Array} array The array to flatten.
* @param {number} depth The maximum recursion depth.
* @param {boolean} [predicate=isFlattenable] The function invoked per iteration.
* @param {boolean} [isStrict] Restrict to values that pass `predicate` checks.
* @param {Array} [result=[]] The initial result value.
* @returns {Array} Returns the new flattened array.
*/
function baseFlatten(array, depth, predicate, isStrict, result) {
var index = -1,
length = array.length;
predicate || (predicate = isFlattenable);
result || (result = []);
while (++index < length) {
var value = array[index];
if (depth > 0 && predicate(value)) {
if (depth > 1) {
// Recursively flatten arrays (susceptible to call stack limits).
baseFlatten(value, depth - 1, predicate, isStrict, result);
} else {
arrayPush(result, value);
}
} else if (!isStrict) {
result[result.length] = value;
}
}
return result;
}
/**
* The base implementation of `getTag` without fallbacks for buggy environments.
*
* @private
* @param {*} value The value to query.
* @returns {string} Returns the `toStringTag`.
*/
function baseGetTag(value) {
if (value == null) {
return value === undefined ? undefinedTag : nullTag;
}
return (symToStringTag && symToStringTag in Object(value))
? getRawTag(value)
: objectToString(value);
}
/**
* The base implementation of `_.isArguments`.
*
* @private
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is an `arguments` object,
*/
function baseIsArguments(value) {
return isObjectLike(value) && baseGetTag(value) == argsTag;
}
/**
* A specialized version of `baseGetTag` which ignores `Symbol.toStringTag` values.
*
* @private
* @param {*} value The value to query.
* @returns {string} Returns the raw `toStringTag`.
*/
function getRawTag(value) {
var isOwn = hasOwnProperty.call(value, symToStringTag),
tag = value[symToStringTag];
try {
value[symToStringTag] = undefined;
var unmasked = true;
} catch (e) {}
var result = nativeObjectToString.call(value);
if (unmasked) {
if (isOwn) {
value[symToStringTag] = tag;
} else {
delete value[symToStringTag];
}
}
return result;
}
/**
* Checks if `value` is a flattenable `arguments` object or array.
*
* @private
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is flattenable, else `false`.
*/
function isFlattenable(value) {
return isArray(value) || isArguments(value) ||
!!(spreadableSymbol && value && value[spreadableSymbol]);
}
/**
* Converts `value` to a string using `Object.prototype.toString`.
*
* @private
* @param {*} value The value to convert.
* @returns {string} Returns the converted string.
*/
function objectToString(value) {
return nativeObjectToString.call(value);
}
/**
* Flattens `array` a single level deep.
*
* @static
* @memberOf _
* @since 0.1.0
* @category Array
* @param {Array} array The array to flatten.
* @returns {Array} Returns the new flattened array.
* @example
*
* _.flatten([1, [2, [3, [4]], 5]]);
* // => [1, 2, [3, [4]], 5]
*/
function flatten(array) {
var length = array == null ? 0 : array.length;
return length ? baseFlatten(array, 1) : [];
}
/**
* Checks if `value` is likely an `arguments` object.
*
* @static
* @memberOf _
* @since 0.1.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is an `arguments` object,
* else `false`.
* @example
*
* _.isArguments(function() { return arguments; }());
* // => true
*
* _.isArguments([1, 2, 3]);
* // => false
*/
var isArguments = baseIsArguments(function() { return arguments; }()) ? baseIsArguments : function(value) {
return isObjectLike(value) && hasOwnProperty.call(value, 'callee') &&
!propertyIsEnumerable.call(value, 'callee');
};
/**
* Checks if `value` is classified as an `Array` object.
*
* @static
* @memberOf _
* @since 0.1.0
* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is an array, else `false`.
* @example
*
* _.isArray([1, 2, 3]);
* // => true
*
* _.isArray(document.body.children);
* // => false
*
* _.isArray('abc');
* // => false
*
* _.isArray(_.noop);
* // => false
*/
var isArray = Array.isArray;
/**
* 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 _
* @since 4.0.0
* @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 != null && typeof value == 'object';
}
module.exports = flatten;
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