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How to Resolve the "SyntaxError: Invalid destructuring assignment target" in JavaScript

The SyntaxError: Invalid destructuring assignment target is a common error that occurs when there is a syntax mistake on the left-hand side of an assignment. It means you are trying to assign a value to something that cannot receive a value, like a literal string or number.

This guide will explain the root cause of this error—the concept of an "assignment target"—and show you how to fix it in the common scenarios where it appears, such as in variable declarations, function parameters, and destructuring reassignments.

The Core Problem: What is an "Assignment Target"?​

In JavaScript, an assignment happens from right to left. The value on the right is assigned to the "target" on the left. The target must be a "writable" location, such as a variable or an object property.

  • Valid: let x = 10; (The target x is a variable).
  • Invalid: 10 = x; (The target 10 is a literal value; you cannot assign something to it).

Destructuring is a more advanced form of assignment, but the same rule applies. The left side of the destructuring must consist of valid targets.

The "Invalid destructuring assignment target" error occurs when you place a literal value where the JavaScript engine expects a variable name.

Scenario 1: Incorrect Variable or Object Declaration​

This error can appear from a simple syntax mistake when declaring a variable.

Example of problem:

// Problem: Using a comma instead of creating an array or separate variables.
let myObject = { name: 'Tom' }, { name: 'John' };
// ⛔️ SyntaxError: Invalid destructuring assignment target
note

This fails because after let myObject = { name: 'Tom' }, the JavaScript parser sees a comma and another object. It tries to interpret this as part of the initial declaration, which is invalid syntax.

Solution: if you intend to create an array of objects, you must wrap them in square brackets [].

// ✅ Solution: Create an array of objects.
let myArray = [{ name: 'Tom' }, { name: 'John' }];

If you meant to declare two separate variables, they must be on different lines or declared differently.

// ✅ Solution: Declare two distinct variables.
let obj1 = { name: 'Tom' };
let obj2 = { name: 'John' };

Scenario 2: Invalid Function Parameter Destructuring​

This is a very common cause of the error. It happens when you try to use a value as a variable name when destructuring a function's arguments.

Example of problem:

// Problem: Using a literal string "value" as the target.
function myFunc({ key: "value" }) {
// ⛔️ SyntaxError: Invalid destructuring assignment target
  console.log('This will not run');
}
note

This is invalid because you are telling JavaScript to "assign the key property from the input object to the literal string "value"," which is impossible.

Solution: your intent was likely one of two things:

1. You wanted to set a default value: The = operator is used for default values, not the : operator.

// ✅ Solution: Set a default value for the entire object parameter.
function myFunc(obj = { key: 'value' }) {
  console.log(obj.key);
}
myFunc(); // Output: "value"

2. You wanted to destructure and rename a property: The : operator is used for renaming, but the new name must be a valid variable identifier, not a literal string.

// ✅ Solution: Destructure `key` and rename it to `newValue`.
function myFunc({ key: newValue }) {
  console.log(newValue);
}
myFunc({ key: 'hello' }); // Output: "hello"

Scenario 3: Incorrect Destructuring Reassignment​

This error can also happen when you try to reassign variables using destructuring after they have been declared.

Example of problem:

let a = 1;
let b = 2;

// Problem: The `{}` are interpreted as a block statement, not an object.
{ a, b } = { a: 10, b: 20 };
// ⛔️ SyntaxError: Invalid destructuring assignment target
note

This is a quirky part of JavaScript syntax. When a line starts with a {, the parser assumes it's the beginning of a code block, not an object literal for an assignment.

Solution: to tell the parser that you intend to perform an assignment, you must wrap the entire statement in parentheses ().

let a = 1;
let b = 2;

// ✅ Solution: Wrap the assignment in parentheses.
({ a, b } = { a: 10, b: 20 });

console.log(a); // Output: 10
console.log(b); // Output: 20

Conclusion​

The SyntaxError: Invalid destructuring assignment target is always a signal that the left-hand side of your assignment or declaration is syntactically incorrect.

  • Remember that the target of an assignment must be a variable or a property that can be written to, not a literal value like a string or number.
  • When destructuring function parameters, use = for default values and : for renaming to a valid variable name.
  • When reassigning with destructuring, wrap the entire statement in parentheses () to avoid syntax ambiguity.

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