158 lines
3.2 KiB
Markdown
158 lines
3.2 KiB
Markdown
<!--
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@license Apache-2.0
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Copyright (c) 2018 The Stdlib Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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# isReadOnlyProperty
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> Test if an object's own property is [read-only][@stdlib/utils/define-read-only-property].
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<section class="usage">
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## Usage
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```javascript
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var isReadOnlyProperty = require( '@stdlib/assert/is-read-only-property' );
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```
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#### isReadOnlyProperty( value, property )
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Returns a `boolean` indicating if a `value` has a [read-only][@stdlib/utils/define-read-only-property] `property`.
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<!-- eslint-disable no-restricted-syntax -->
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```javascript
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var defineProperty = require( '@stdlib/utils/define-property' );
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var obj = {
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'foo': 'bar'
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};
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defineProperty( obj, 'beep', {
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'configurable': false,
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'enumerable': false,
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'writable': false,
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'value': 'boop'
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});
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defineProperty( obj, 'accessor', {
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'configurable': false,
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'enumerable': true,
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'get': function getter() {
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return obj.foo;
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}
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});
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var bool = isReadOnlyProperty( obj, 'foo' );
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// returns false
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bool = isReadOnlyProperty( obj, 'beep' );
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// returns true
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bool = isReadOnlyProperty( obj, 'accessor' );
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// returns true
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```
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</section>
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<!-- /.usage -->
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<section class="notes">
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## Notes
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- Value arguments other than `null` or `undefined` are coerced to `objects`.
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```javascript
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var bool = isReadOnlyProperty( 'beep', 'length' );
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// returns true
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```
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- Property arguments are coerced to `strings`.
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```javascript
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var defineProperty = require( '@stdlib/utils/define-property' );
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var obj = {};
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defineProperty( obj, 'null', {
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'configurable': false,
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'enumerable': true,
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'writable': false,
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'value': true
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});
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var bool = isReadOnlyProperty( obj, null );
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// returns true
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```
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</section>
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<!-- /.notes -->
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<section class="examples">
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## Examples
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<!-- eslint-disable object-curly-newline -->
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<!-- eslint no-undef: "error" -->
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```javascript
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var isReadOnlyProperty = require( '@stdlib/assert/is-read-only-property' );
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var bool = isReadOnlyProperty( 'a', 'length' );
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// returns true
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bool = isReadOnlyProperty( { 'a': 'b' }, 'a' );
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// returns false
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bool = isReadOnlyProperty( [ 'a' ], 0 );
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// returns false
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bool = isReadOnlyProperty( { 'null': false }, null );
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// returns false
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bool = isReadOnlyProperty( { '[object Object]': false }, {} );
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// returns false
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bool = isReadOnlyProperty( {}, 'toString' );
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// returns false
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bool = isReadOnlyProperty( {}, 'hasOwnProperty' );
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// returns false
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bool = isReadOnlyProperty( null, 'a' );
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// returns false
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bool = isReadOnlyProperty( void 0, 'a' );
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// returns false
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```
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</section>
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<!-- /.examples -->
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<section class="links">
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[@stdlib/utils/define-read-only-property]: https://www.npmjs.com/package/@stdlib/utils-define-read-only-property
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</section>
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<!-- /.links -->
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