cannot read property
/* This error occurs in Chrome Browser when you read a property or call
a method on an undefined object. */
// To handle it, use "Optional Chaining" compatible with Node.js v14.0.0
Syntax -> ?.
Usage ->
let obj;
console.log(obj.a) // Cannot read property 'a' of undefined
console.log(obj?.a) // Works like a charm
4.1
10
Seems like one of your values, with a property key of 'value' is undefined. Test that i1, i2and __i are defined before executing the if statements:
var i1 = document.getElementById('i1');
var i2 = document.getElementById('i2');
var __i = {'user' : document.getElementsByName("username")[0], 'pass' : document.getElementsByName("password")[0] };
if(i1 && i2 && __i.user && __i.pass)
{
if( __i.user.value.length >= 1 ) { i1.value = ''; } else { i1.value = 'Acc'; }
if( __i.pass.value.length >= 1 ) { i2.value = ''; } else { i2.value = 'Pwd'; }
}
Thank you!
10
4.1
(10 Votes)
0
4.75
4
JavaScript TypeError is thrown when an operand or argument passed to a function is incompatible with the type expected by that operator or function. This error occurs in Chrome Browser when you read a property or call a method on an undefined object .JavaScript TypeError is thrown when an operand or argument passed to a function is incompatible with the type expected by that operator or function. This error occurs in Chrome Browser when you read a property or call a method on an undefined object .
Thank you!
4
4.75
(4 Votes)
0
0
5
// That is mostly because the object was not declared until the moment when the code ran,
// Example:
console.log(object.list.map(el => el.name))
const object = {
list: [
{name: 'test'},
{name: 'second'}
]
}
// The error happens because the object was created after the map call
// The same happens if you forgot to import a package for example.
// If you are dealing with a situation that you don't know if the object
// has an specific property, you can use a question mark to tell the compiler
// that maybe the property doesen't exists, returning undefined:
console.log(object.default.size) // error
console.log(object.list[1]?.age) // undefined
console.log(object.default?.color) // undefined
Thank you!
5
0
0
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