/** * @license Apache-2.0 * * Copyright (c) 2018 The Stdlib Authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ 'use strict'; // MODULES // var MAX_SAFE_INTEGER = require( '@stdlib/constants/float64/max-safe-integer' ); var isPositiveInteger = require( '@stdlib/assert/is-positive-integer' ).isPrimitive; var isEnumerableProperty = require( '@stdlib/assert/is-enumerable-property' ); var getOwnPropertySymbols = require( './../../property-symbols' ); var getPrototypeOf = require( './../../get-prototype-of' ); var hasOwnProp = require( '@stdlib/assert/has-own-property' ); // MAIN // /** * Returns an array of an object's inherited enumerable symbol properties. * * @param {*} value - input object * @param {PositiveInteger} [level] - inheritance level * @throws {TypeError} second argument must be a positive integer * @returns {Array} a list of inherited enumerable symbol properties * * @example * var symbols = inheritedEnumerablePropertySymbols( [] ); */ function inheritedEnumerablePropertySymbols( value, level ) { // eslint-disable-line id-length var cache; var out; var obj; var tmp; var N; var n; var k; var i; if ( arguments.length > 1 ) { if ( !isPositiveInteger( level ) ) { throw new TypeError( 'invalid argument. Second argument must be a positive integer. Value: `' + level + '`.' ); } N = level; } else { N = MAX_SAFE_INTEGER; } if ( value === null || value === void 0 ) { return []; } // Get the value's prototype: obj = getPrototypeOf( value ); // Walk the prototype chain collecting enumerable symbol properties... cache = {}; out = []; n = 1; while ( obj && n <= N ) { tmp = getOwnPropertySymbols( obj ); for ( i = 0; i < tmp.length; i++ ) { k = tmp[ i ]; if ( hasOwnProp( cache, k ) === false && isEnumerableProperty( obj, k ) ) { out.push( k ); } cache[ k ] = true; } obj = getPrototypeOf( obj ); n += 1; } return out; } // EXPORTS // module.exports = inheritedEnumerablePropertySymbols;