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