Syntax Errors in JavaScript

TL ; DR:

• Syntax errors are mistakes in the use of the JavaScript language, analogous to spelling or grammar mistakes in a language like English. For example:

  
  

• Omitting quotes when working with strings:

  console.log("Welcome!);
  

  
  

• Omitting parantheses when using the console.log function:

  console.log("Let's code!";
  

  
  

• When JavaScript encounters a syntax error, it immediately stops executing your code and throws a SyntaxError instead.

Full lesson:

Humans are prone to making mistakes. Humans are also typically in charge of creating computer programs. To compensate, programming languages attempt to understand and explain mistakes made in their programs.

Here are two common errors that we encounter while writing JavaScript code:

The SyntaxError:

Syntax errors are mistakes in the use of the JavaScript language, and are analogous to spelling or grammar mistakes in a language like English. For example, the sentence "Would you some tea?" does not make sense – it is missing a verb.

SyntaxError means there is something wrong with the way your program is written. Some examples:

1. Misuse of commas when declaring a string:

let greeting = 'Hey there!";

When we run this code we'll get a SyntaxError: Invalid or unexpected token.

2. Leaving out a parantheses:

console.log"My name is Andy");

When we run this code we'll get a SyntaxError: Unexpected string.

The ReferenceError:

A ReferenceError occurs when the JavaScript interpreter sees a word it does not recognize. Some examples:

1. Misspelling a class / function name:

consle.log("My name is Andy");

When we run this code we'll get a ReferenceError: consle is not defined.

2. Using a non-existent variable / Misspelling a variable's name:

let animal = "parrot";
console.log(aniimal);

When we run this code we'll get a ReferenceError: aniimal is not defined.

Assignment
Follow the Coding Tutorial and let's practice with errors!

Hint
Look at the examples above if you get stuck.