The “Uncaught SyntaxError: Unexpected identifier” error is a syntax error that occurs when the JavaScript interpreter encounters an unexpected identifier (i.e., a variable or function name) in the code. This error typically indicates that there is a syntax mistake in the code that is preventing the interpreter from parsing it correctly.
For example, if you’re trying to execute the following code:
const user = {
name: 'John Doe',
age: 30
}
console.log(user.name);
console.log(user.age);You will not get the error because the code is correct and valid. However, if you were to modify the code like this:
const user = {
name: 'John Doe'
age: 30
}
console.log(user.name);
console.log(user.age);You would get the “Uncaught SyntaxError: Unexpected identifier” error because the JSON object is missing a comma between the "name" and "age" properties. This is a syntax error, and the interpreter cannot parse the code correctly.
Some other reasons for encountering this error include:
- Forgetting to add a closing parenthesis, bracket, or brace in your code;
- Using a reserved word as a variable or function name;
- Using a dot (
.) instead of a comma (,) in an object or array literal; - Using a non-existent property or method of an object;
- Using an undeclared variable in your code;
- Using a template literal inside a string that is itself inside a template literal.
That’s a lot of reasons, right? The best way to avoid this error altogether is to use a linter or code formatter. A linter is a tool that analyzes your code for potential errors and problems, such as syntax errors, coding style violations, and other issues.
In addition to linters, you can also use a code formatter, such as Prettier, to automatically format and lint your code. Code formatters can help you avoid syntax errors by automatically formatting your code according to a specific style guide and fixing any common syntax mistakes.
By using a linter or code formatter, you can automate the process of spotting syntax errors in your code and avoid the “Uncaught SyntaxError: Unexpected identifier” error and other common mistakes.