something wrong when I use this package

[ChenRuihua]

I use this package like this:

use DecimalObjectCast;
protected $casts = [
'price' => 'decimal',
'amount' => 'decimal',
];

but have error.

Declaration of Decimal\DecimalObjectCast::asDecimal(Decimal\Decimal $value, $decimals) should be compatible with Illuminate\Database\Eloquent\Model::asDecimal($value, $decimals)

is there have a readme about this package?

[rtheunissen]

Can you install version 1.1.2 and see if there are any issues in your environment?

[Peter-Krebs]

Have you checked the usage of decimal casts without the package?

See Laravel documentation
Probably the solution to your problem: The Laravel docs say you must specify number of digits for casts to type decimal, for example 'price' => 'decimal:64' instead of just 'decimal'.

See: Laravel Eloquent Mutators: Attribute casting

[barryp]

Just FYI, for Laravel 7.x and up it might be easier to define a Custom Cast class - with a get() method that converts the null|string value from the DB to a null|Decimal, and a set() method that does the reverse.