Cannot read properties of null (reading 'getContext')

vinoth kumar

when i work on pattern lock on canvas getting the error.i connect the first two dots its not pblm when i connect the third dots.it get error.

Thanks in advance

1 Reply

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Vishal Joshi3y ago

Hello Vinoth,

You need to check if the object is null before trying to get the value from the third dot(.).

JSON Example:

ObjectA
{
  item1:'abc',
  subObjA:
  {
    subItem1:'xyz',
    subObjAA:
    {
      item:'pqr',
    }
  }
}

//In the Above case we can Get a third dot (.) value like below
let value = ObjectA.subObjA.subObjAA.item

But if we don't have subObjAA defined then it will throw exceptions like can not read null properties.

it would help if you tried the below syntax to handle null values.

let value = ObjectA?.subObjA?.subObjAA.item

Thanks