When altering the behavior of existing Object.prototype methods, consider injecting code by wrapping your extension before or after the existing logic. For example, this (untested) code will pre-conditionally execute custom logic before the built-in logic or someone else's extension is executed.
When modifying prototypes with hooks, pass this and the arguments (the call state) to the current behavior by calling apply() on the function. This pattern can be used for any prototype, such as Node.prototype, Function.prototype, etc.
script.js
const current = Object.prototype.valueOf;
// Since my property "-prop-value" is cross-cutting and isn't always
// on the same prototype chain, I want to modify Object.prototype:
Object.prototype.valueOf = function (...args) {
if (Object.hasOwn(this, "-prop-value")) {
return this["-prop-value"];
} else {
// It doesn't look like one of my objects, so let's fall back on
// the default behavior by reproducing the current behavior as best we can.
// The apply behaves like "super" in some other languages.
// Even though valueOf() doesn't take arguments, some other hook may.
return current.apply(this, args);
}
};
Warning: Modifying the prototype property of any built-in constructor is considered a bad practice and risks forward compatibility.
When altering the behavior of existing Object.prototype methods, consider injecting code by wrapping your extension before or after the existing logic. For example, this (untested) code will pre-conditionally execute custom logic before the built-in logic or someone else's extension is executed.
When modifying prototypes with hooks, pass this and the arguments (the call state) to the current behavior by calling apply() on the function. This pattern can be used for any prototype, such as Node.prototype, Function.prototype, etc.
script.js
Warning: Modifying the prototype property of any built-in constructor is considered a bad practice and risks forward compatibility.
You can read more about prototypes in Inheritance and the prototype chain.