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