TrustedTypePolicyFactory: isScript() method

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Note: This feature is available in Web Workers.

The isScript() method of the TrustedTypePolicyFactory interface returns true if it is passed a valid TrustedScript object.

Note: The purpose of the functions isScript(), isHTML(), and isScriptURL() is to check if the object is a valid TrustedType object, created by a configured policy.

Syntax

isScript(value)

Return value

A boolean that is true if the object is a valid TrustedScript object.

In the below example the constant url was created by a policy, and therefore isScriptURL() returns true. The second example is an attempt to fake an object, and the third is a string. Both of these will return false when passed to isScriptURL().

const myScript = policy.createScript("eval('2 + 2')");
console.log(trustedTypes.isScript(myScript)); // true;

const fake = Object.create(TrustedScript.prototype);
console.log(trustedTypes.isScript(fake)); // false

console.log(trustedTypes.isScript("eval('2 + 2')")); // false