JavaScript Safe Assignment Operator : Alternative to try/catch

Attention

I would like to point out that Safe Assignment Operator must be supported with polyfill since it is not yet in the ECMAScript standard. In this article, we will explore how to use the safe assignment operator when it is in the ECMAScript standard.

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We use try/catch for error handling when developing with JavaScript, especially when working with asynchronous functions or complex APIs. ECMAScript announced a new operator. The Safe Assignment Operator (?=) simplifies error handling and provides a uniform structure for handling results and errors, especially during asynchronous operations.

When you use the safe assignment operator, it checks a function or operation was successful. If successful, it returns the result. Returns error if unsuccessful.

Now let's explore how to use the Safe Assignment Operator (?=).

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Now let's write the syntax for an api request of the safe assignment operator.

async function fetchData() {
  const [error, response] ?= await fetch("https://jsonplaceholder.typicode.com/todos/1"); // safe assigment op.

  if (error) {
    console.error("Fetch error:", error);
    return;
  }

  const [jsonError, jsonData] ?= await response.json();

  if (jsonError) {
    console.error("JSON error:", jsonError);
    return;
  }

  return jsonData;
}

In API requests, an object is returned at each step; This object stores information related to the request. We can use the object destructuring feature to get the data inside this object. With the** Safe Assignment Operator** (?=), when an error occurs in the API request, we can safely retrieve the error message or error code by handling the error object with the destructuring method. const [error, response], error returns the error. response returns the data

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Usage in Objects and Functions

The ?= operator can be used with an object or function that implements the Symbol.result method.

• Objects:

const objSafe = {
  [Symbol.result]() {
    return [new Error("Object error"), null];
  }
};

const [error, result] ?= objSafe;
console.log(error)

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• Functions:

function safeOperator(arr) {
  return 'data';
}

const [error, result] = safeOperator[Symbol.result](arr);

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Conclusion

In this article, we have examined how to use the safe assignment operator when it is in the ECMAScript standard. I think he's a very useful operator. now we know how to use it.

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