➕in
`prop in obj`
JS ⟩ statement ⟩ expression ⟩ operator ⟩ relational ⟩ in
// ⭐️ check if `prop` is property of `obj` (including inherited)
prop in obj // ⭐️ prop: string-convertable expressionreplit： "in" operator
let point = {x: 1, y: 2};
let array = [1, 2, 3];
'x' in point, // true
'z' in point, // false
'toString' in point, // true (inherited)
'0' in array, // true
1 in array, // true (1 -> '1')
3 in array, // false (3 -> '3', no such prop)
'toString' in array, // true (inherited)Last updated