ReferenceError: deprecated caller or arguments usage
The JavaScript strict mode-only exception
"deprecated caller or arguments usage" occurs when the
deprecated Function.prototype.caller or Function.prototype.arguments properties
are used.
Message
TypeError: 'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them (V8-based & Firefox) TypeError: 'arguments', 'callee', and 'caller' cannot be accessed in this context. (Safari)
Error type
TypeError in strict mode only.
What went wrong?
In strict mode, the
Function.prototype.caller or Function.prototype.arguments properties are used
and shouldn't be. They are deprecated, because they leak the function caller, are
non-standard, hard to optimize and potentially a performance-harmful feature.
Examples
Deprecated function.caller or arguments.callee.caller
Function.prototype.caller and
arguments.callee.caller
are deprecated (see the reference articles for more information).
js
"use strict";
function myFunc() {
if (myFunc.caller === null) {
return "The function was called from the top!";
} else {
return `This function's caller was ${myFunc.caller}`;
}
}
myFunc();
// TypeError: 'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them
Function.prototype.arguments
Function.prototype.arguments is deprecated (see the reference article for more
information).
js
"use strict";
function f(n) {
g(n - 1);
}
function g(n) {
console.log(`before: ${g.arguments[0]}`);
if (n > 0) {
f(n);
}
console.log(`after: ${g.arguments[0]}`);
}
f(2);
console.log(`returned: ${g.arguments}`);
// TypeError: 'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them