| JS_LookupProperty |
Function |
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Summary
Determines if a specified property exists.
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Syntax
JSBool JS_LookupProperty(JSContext *cx, JSObject *obj,
const char *name, jsval *vp);
| Name | Type | Description |
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cx | JSContext * | Pointer to a JS context from which to derive runtime information.
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obj | JSObject * | Object to search on for the property.
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name | const char * | Name of the property to look up.
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vp | jsval * | Pointer to a variable into which to store the last retrieved value of the property if it exists. If not, vp is set to JSVAL_VOID.
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Description
JS_LookupProperty examines a specified JS object, obj, for a property named name. If the property exists, vp is set either to the last retrieved value of the property if it exists, or to JSVAL_VOID if it does not, and JS_LookupProperty returns JS_TRUE. On error, such as running out of memory during the search, JS_LookupProperty returns JS_FALSE, and vp is undefined.
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Notes
JS_LookupProperty does not distunguish between a property with a value of undefined and a property that does not exist. Use JS_GetPropertyAttributes to distinguish these cases.
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See Also
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