The allowsFeature()
method of the FeaturePolicy
interface enables introspection of individual directives of the Feature Policy it is run on. It returns a Boolean
that is true
if and only if the specified feature is allowed in the specified context (or the default context if no context is specified).
const allowed = FeaturePolicy.allowsFeature(<feature>)
or
const allowed = FeaturePolicy.allowsFeature(<feature>, <origin>)
Feature name
A specific feature name must be specified.
Origin name
Optional
An origin URL to check the feature on. If it is omitted the default origin is used.
A Boolean
that is true
if and only if the feature is allowed.
The following example queries whether or not the document is allowed to use camera API by the Feature Policy. Please note that Camera API might be restricted by the Permissions API, if the user did not grant the corresponding permission yet.
const featurePolicy = document.featurePolicy
const allowed = featurePolicy.allowsFeature("camera")
if (allowed){
console.log("FP allows camera.")
} else {
console.log("FP does not allows camera.")
}