Prefer that
for-in loops should include an if statement JS-0051
Anti-pattern
Minor
8 months ago
—
a year old
No results found
That’s all we can say right now.
Description
Looping over objects with a for in loop will include properties that are inherited through the prototype chain.
This behavior can lead to unexpected keys in your for loop.
Bad Practice
for (const key in foo) {
doSomething(key);
}
Recommended
for (const key in foo) {
if (Object.prototype.hasOwnProperty.call(foo, key)) {
doSomething(key);
}
}
for (const key of Object.keys(foo)) {
doSomething(key);
}