Ethereum: TypeError: X is not a function (Uncaught (in promise) error)
Ethereum Error: Typeerror: X is not a function
As a programmer working with Ethereum Smart Contracts, you are probably not a stranger to the complex world of programming languages and libraries. However, using some methods in the Ethereum contract you can encounter a mistake that at first glance seems senseless. In this article, we delve into the details of what causes this problem and we provide a solution.
Problem: Typeerror: X is not a function
When you try to call the method on the Ethereum contract using “Contract.Methods.metHodname (), he says thatXis not a function. This may seem like a general error message, but in fact it is more detailed.
Problem: an unrelated designer
In most programming languages, including JavaScript and some other libraries, when you call the method on the object without determining the object itself (i.e. "x), he will look for the function of a designer defined elsewhere. However, in this case we work with a contract, not a class.
correction: Bind the constructor
To resolve this problem, you must link the contract designer to the contract of the contract itself. This is done using the bind () method provided by the" call "function.
Javascript
contract.methods.mythod.bind (this). Call ();
In this example, we bind the designer “Mymethodto" This "(ie the instance of our contract), which allows us to call it without the term" x.
best practices
To avoid similar problems in the future:
1
- Use the “bind () method
When calling the method of the contract.
When using these amendments and the best practices, you should be able to solve Typeerror: X is not a mistake associated with the Ethereum Smart contract.
Sample code
Here is an example fragment of the code that shows how to solve this problem:
Javascript
Import * as the ethere of "ether";
Const Mycontract = Artfacts.require ("Mycontract");
contract ("Mycontract", async (accounts) => {
const instance = wait for mycontract.new ();
Const mymethod = instance.methods.methhod;
// Call mymethod without determining x
console.log (waiting for MyMethod ()); // Exit: Typeerror error: X is not a function
// with the help of bind () To determine this, we fix the problem:
Const result = wait for mymethod.bind (this) .Call ();
console.log (result);
});
Remember to replace “MyContract” with the actual name of the contract and modify the code accordingly.
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