Function objForEachKey

Calls the provided callbackFn function once for each key in an object. This is equivalent to arrForEach(Object.keys(theObject), callbackFn) or if not using the array helper Object.keys(theObject).forEach(callbackFn) except that this helper avoids creating a temporary array of the object keys before iterating over them and like the arrForEach helper you CAN stop or break the iteration by returning -1 from the callbackFn function.

Note: This helper only iterates string (and numeric) keys (via for...in loop) and does NOT include enumerable symbol keys. If you need to iterate all keys including symbol, use forEachOwnKey or forEachOwnKeySafe instead.

Caution: this helper does not filter unsafe keys like __proto__, constructor, or prototype. If your callback uses the returned key to assign directly to another object (for example target[key] = value), validate keys first (for example with isUnsafePropKey) or use objForEachKeySafe when iterating untrusted input.

// Basic iteration - only string keys
const obj = { name: "Alice", age: 30 };
objForEachKey(obj, (key, value) => {
    console.log(key, value);  // name Alice, age 30
});
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// Unsafe keys warning - use objForEachKeySafe for untrusted input
// Note: use Object.defineProperty (not an object literal) so "__proto__" is
// created as a normal own enumerable property rather than being treated
// specially by the JS engine.
const untrustedObj: any = { name: "Bob" };
Object.defineProperty(untrustedObj, "__proto__", { value: "attack", enumerable: true, configurable: true, writable: true });
objForEachKey(untrustedObj, (key, value) => {
    console.log(key, value);  // name Bob, __proto__ attack (UNSAFE!)
});

// Safe iteration with objForEachKeySafe
objForEachKeySafe(untrustedObj, (key, value) => {
    console.log(key, value);  // name Bob (unsafe keys filtered)
});
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