103 lines
2.9 KiB
JavaScript
103 lines
2.9 KiB
JavaScript
/**
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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 isObjectLike = require( '@stdlib/assert-is-object-like' );
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var hasOwnProp = require( '@stdlib/assert-has-own-property' );
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var isArguments = require( '@stdlib/assert-is-arguments' );
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var HAS_ENUM_PROTO_BUG = require( './has_enumerable_prototype_bug.js' );
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var HAS_NON_ENUM_PROPS_BUG = require( './has_non_enumerable_properties_bug.js' );
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var isConstructorPrototype = require( './is_constructor_prototype_wrapper.js' );
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var NON_ENUMERABLE = require( './non_enumerable.json' );
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// MAIN //
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/**
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* Returns an array of an object's own enumerable property names.
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*
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* @private
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* @param {*} value - input object
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* @returns {Array} a list of own enumerable property names
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*
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* @example
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* var obj = {
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* 'beep': 'boop',
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* 'foo': 3.14
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* };
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*
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* var k = keys( obj );
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* // e.g., returns [ 'beep', 'foo' ]
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*/
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function keys( value ) {
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var skipConstructor;
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var skipPrototype;
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var isFcn;
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var out;
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var k;
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var p;
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var i;
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out = [];
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if ( isArguments( value ) ) {
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// Account for environments which treat `arguments` differently...
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for ( i = 0; i < value.length; i++ ) {
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out.push( i.toString() );
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}
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// Note: yes, we are precluding the `arguments` array-like object from having other enumerable properties; however, this should (1) be very rare and (2) not be encouraged (e.g., doing something like `arguments.a = 'b'`; in certain engines directly manipulating the `arguments` value results in automatic de-optimization).
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return out;
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}
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if ( typeof value === 'string' ) {
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// Account for environments which do not treat string character indices as "own" properties...
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if ( value.length > 0 && !hasOwnProp( value, '0' ) ) {
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for ( i = 0; i < value.length; i++ ) {
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out.push( i.toString() );
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}
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}
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} else {
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isFcn = ( typeof value === 'function' );
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if ( isFcn === false && !isObjectLike( value ) ) {
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return out;
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}
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skipPrototype = ( HAS_ENUM_PROTO_BUG && isFcn );
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}
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for ( k in value ) {
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if ( !( skipPrototype && k === 'prototype' ) && hasOwnProp( value, k ) ) {
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out.push( String( k ) );
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}
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}
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if ( HAS_NON_ENUM_PROPS_BUG ) {
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skipConstructor = isConstructorPrototype( value );
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for ( i = 0; i < NON_ENUMERABLE.length; i++ ) {
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p = NON_ENUMERABLE[ i ];
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if ( !( skipConstructor && p === 'constructor' ) && hasOwnProp( value, p ) ) {
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out.push( String( p ) );
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}
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}
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}
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return out;
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}
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// EXPORTS //
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module.exports = keys;
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