告诉我,如何正确地检查关联数组中的键是否存在?
例如:
例如:
var mydata = {
key1: '',
key2: {
subkey1: {
subkey1_1: {
value1: ''
value2" '',
},
},
subkey2: '';
},
}
if ((mydata.key2 != undefined) && (mydata.key2.subkey1 != undefined) && (mydata.key2.subkey1.subkey1_1 != undefined))
mydata.key2.subkey1.subkey1_1.value1 = 'test';
过长且令人困惑
((mydata.key2 != undefined) && (mydata.key2.subkey1 != undefined) && (mydata.key2.subkey1.subkey1_1 != undefined))
我希望使用一个更简单的函数,比如
safeSet(mydata.key2.subkey1.subkey1_1.value1, 'test');
或者
if (is_undefined(mydata.key2.subkey1.subkey1_1.value1) == true)
mydata.key2.subkey1.subkey1_1.value1 = 'test'; // now - error if 'mydata.key2.subkey1.subkey1_1' not exist
try/catch
块。 - Rory McCrossan