JavaScript - Keywords
Here are some common keywords in JavaScript:
- var: used to declare variables in JavaScript. It has function-level scope and its value can be changed within the function.
- let: used to declare variables in JavaScript with block-level scope. The value of a let variable can be changed within its scope.
- const: used to declare variables in JavaScript with block-level scope that cannot be changed.
- function: used to declare a function in JavaScript. Functions are reusable blocks of code that can be executed when called.
- return: used to return a value from a function. The code execution will exit the function and return the specified value.
- if: used to perform conditional logic in JavaScript. If the condition specified in the if statement is true, the code block within the if statement will be executed.
- else: used in conjunction with if statement to provide an alternative code block to be executed if the if condition is false.
- switch: used to perform multiple conditional operations. A switch statement compares the value of an expression with multiple case labels, and the code block associated with the first matching case label will be executed.
- while: used to repeat a block of code while a specified condition is true. The code block will be executed repeatedly until the condition becomes false.
- for: used to repeat a block of code a specified number of times. The for loop is often used to iterate over arrays and objects.
- this: refers to the object that is executing the current function. The value of this can change based on how the function is called.
- new: used to create an instance of an object in JavaScript. When used with a constructor function, the new operator creates a new object and sets the value of this to the new object within the constructor function.
- try: used to handle exceptions and errors in JavaScript. A try block contains code that might throw an exception, and the associated catch block contains the code to be executed in case an exception is thrown.
- instanceof: used to check if an object is an instance of a specified object type. It returns true if the object is an instance of the specified type, and false otherwise.
- typeof: used to check the data type of a variable in JavaScript. It returns a string indicating the type of the variable.
- delete: used to delete a property from an object in JavaScript. When used with an object property, it deletes the property and its value.
- void: used to evaluate an expression and return undefined. It is often used to evaluate expressions for their side effects without using their returned value.