SyntaxError: Unexpected identifier in JavaScript [Solved]

# SyntaxError: Unexpected identifier in JavaScript [Solved]

The "Uncaught SyntaxError: Unexpected identifier" error occurs for 2 main reasons:

1. Misspelling a keyword, e.g. Let or Class instead of let and class.
2. Having a typo in your code, e.g. a missing or extra comma, parenthesis, quote or bracket.

Here are some common examples of how the error occurs.

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// ⛔️ Uncaught SyntaxError: Unexpected identifier
Let age = 30; // 👈️ should be let

// ⛔️ Uncaught SyntaxError
Class Person { // 👈️ should be class

}

// ⛔️ Uncaught SyntaxError
Function sum(a,b) { // 👈️ should be function
  return a + b;
}

// ⛔️ Uncaught SyntaxError
const obj = {
  first: 'Bobby' // 👈️ missing comma
  last: 'Hadz',
};

Var example = 'hello' // 👈️ should be var

The first and second examples show how misspelling a keyword causes the error. Keywords are case-sensitive.

Here is how to resolve the error in these particular cases.

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let age = 30; //️ ✅ let (lowercase l)

class Person { // ✅ class (lowercase c)

}

function sum(a,b) { // ✅ function (lowercase f)
  return a + b;
}

const obj = {
  first: 'Bobby', // ✅ added missing comma
  last: 'Hadz',
};

var example = 'hello' // ✅ var (lowercase v)

The error message should display the name of the file and the line on which the error occurred.

# The most common causes of the error

The most common causes of the error are:

• misspelled or incorrect keywords like Let, Const, Class or Function
• a missing colon, comma, bracket, parenthesis or quote
• an extra colon, comma, bracket, parenthesis or quote

The syntax of a for loop can be quite tricky, so make sure you don't have any syntactical errors if you use any for loop.

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const arr = ['bobby', 'hadz', 'com'];

for (let index = 0; index < arr.length; index++) {
  // ✅ bobby, hadz, com
  console.log(arr[index]);
}

# Having a missing comma

Make sure you don't have any missing commas between the properties of an object or an array's elements.

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const obj = {
  first: 'Bobby' // 👈️ missing comma
  last: 'Hadz',
};

const arr = ['bobby' 'hadz', 'com'] // 👈️ missing comma

To solve the error, separate the key-value pairs of an object or the array's element by commas.

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const obj = {
  first: 'Bobby',
  last: 'Hadz',
};

const arr = ['bobby', 'hadz', 'com'];

When working with objects, it is recommended to add a trailing comma after the last key-value pair.

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const obj = {
  name: 'bobby',
  id: 5,
  age: 30, // 👈️ add trailing comma
};

This way you don't have to remember to add a comma before adding the next key-value pair to the object.

You can also hover over the squiggly red line to get additional information.

# Conclusion

To solve the "Uncaught SyntaxError: Unexpected identifier" error, make sure you don't have any misspelled keywords, e.g. Let or Function instead of let and function and correct any typos related to a missing or an extra comma, colon, parenthesis, quote or bracket.