isNonConfigurablePropertyIn

Test if an object's own or inherited property is non-configurable.

Usage

var isNonConfigurablePropertyIn = require( '@stdlib/assert/is-nonconfigurable-property-in' );

isNonConfigurablePropertyIn( value, property )

Returns a boolean indicating if a value has a non-configurable property (i.e., a property which cannot be deleted and whose descriptor cannot be changed).

var defineProperty = require( '@stdlib/utils/define-property' ); var bool; var obj; function Foo() { this.foo = 'bar'; return this; } defineProperty( Foo.prototype, 'beep', { 'configurable': true, 'enumerable': true, 'writable': true, 'value': true }); defineProperty( Foo.prototype, 'boop', { 'configurable': false, 'enumerable': true, 'writable': true, 'value': true }); obj = new Foo(); bool = isNonConfigurablePropertyIn( obj, 'foo' ); // returns false bool = isNonConfigurablePropertyIn( obj, 'beep' ); // returns false bool = isNonConfigurablePropertyIn( obj, 'boop' ); // returns true

Notes

  • Value arguments other than null or undefined are coerced to objects.

    var bool = isNonConfigurablePropertyIn( 'beep', 'length' ); // returns true

  • Non-symbol property arguments are coerced to strings.

    var defineProperty = require( '@stdlib/utils/define-property' ); var obj = {}; defineProperty( obj, 'null', { 'configurable': false, 'enumerable': true, 'writable': true, 'value': true }); var bool = isNonConfigurablePropertyIn( obj, null ); // returns true

Examples

var isNonConfigurablePropertyIn = require( '@stdlib/assert/is-nonconfigurable-property-in' ); var bool = isNonConfigurablePropertyIn( [ 'a' ], 'length' ); // returns true bool = isNonConfigurablePropertyIn( {}, 'toString' ); // returns false bool = isNonConfigurablePropertyIn( {}, 'hasOwnProperty' ); // returns false bool = isNonConfigurablePropertyIn( { 'a': 'b' }, 'a' ); // returns false bool = isNonConfigurablePropertyIn( [ 'a' ], 0 ); // returns false bool = isNonConfigurablePropertyIn( { 'null': false }, null ); // returns false bool = isNonConfigurablePropertyIn( { '[object Object]': false }, {} ); // returns false bool = isNonConfigurablePropertyIn( null, 'a' ); // returns false bool = isNonConfigurablePropertyIn( void 0, 'a' ); // returns false

See Also