js 如何删除对象中的一个属性

Deleting Properties

The only way to actually remove a property from an object is to use the

delete

operator;
setting the property to

undefined

or

null

only
remove the value associated
with the property, but not the key.

var obj = {
    bar: 1,
    foo: 2,
    baz: 3
};
obj.bar = undefined;
obj.foo = null;
delete obj.baz;

for(var i in obj) {
    if (obj.hasOwnProperty(i)) {
        console.log(i, '' + obj[i]);
    }
}

The above outputs both

bar
 undefined

and

foo
 null

- only

baz

was
removed and is therefore missing from the output.