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JavaScript Functions

Functions Study Path

Learn Functions in the Right Order

  • First the idea
  • Then how to make them
  • Then how to use them

Step 1 Beginner

  • Functions are reusable code blocks designed for particular tasks
  • Functions are executed when they are called or invoked
  • Functions are fundamental in all programming languages

Step 2 Beginner

  • Functions are executed when they are called or invoked
  • You call a function by adding parentheses to its name: name()

Step 3 Beginner

  • Parameters allow you to send values to a function
  • Parameters are listed in parentheses in the function definition

Step 4 Beginner

  • A function can return a value back to the code that called it
  • The return statement is used to return a value from a function

Step 5 Intermediate

  • Function parameters and arguments are distinct concepts
  • Parameters are the names listed in the function definition
  • Arguments are the values received by the function

Step 6 Intermediate

  • A function expression is a function stored in a variable
  • The variable name can be used to call the function

Step 7 Intermediate

  • Arrow Functions is a short syntax for function expressions
  • You can skip the function keyword
  • You can skip the return keyword
  • You can skip the curly brackets

Step 8 Intermediate

  • Test your knowledge of JavaScript functions
  • The quiz uses the examples you learned in the tutorial

Advanced Functions Study Path

Step 1 Advanced

  • Function declarations
  • Function Expression
  • Arrow Functions
  • Function Constructors

Step 2 Advanced

A JavaScript callback is a function passed as an argument to another function, which is then executed (or "called back") at a later point in time to complete a specific task.

Step 3 Advanced

How this works (especially inside objects).

How this is decided by how it is called.

Step 4 Advanced

Call a function with a chosen this .

Pass a list of arguments.

Step 5 Advanced

Call a function with a chosen this .

Pass an array of arguments.

Step 6 Advanced

Call a function with a chosen this .

Use bind() when you need a function to run later with the same this .

Step 7 Advanced

Self-starting functions.

Step 8 Advanced

Functions that remember their scope

Learn how functions can remember variables after the outer function finishes.

Step 9 Advanced

Function Object Methods & Properties.

Previous

JavaScript Loops

Next

JavaScript Scope

This chapter

Overview
51

Lessons

194m

Read time

1. JavaScript Tutorial2. JavaScript Syntax3. JavaScript Operators4. JavaScript if5. JavaScript Loops6. JavaScript Functions7. JavaScript Scope8. JavaScript Data Types9. JavaScript Style Guide10. JavaScript Introduction11. JavaScript Statements12. JavaScript Arithmetic13. JavaScript else14. JavaScript For Loop15. JavaScript Functions16. JavaScript Code Blocks17. JavaScript Primitives18. JavaScript Best Practices19. JavaScript Where To20. JavaScript Comments21. JavaScript Assignment22. The JavaScript Ternary Operator23. JavaScript While Loops24. Invoking JavaScript Functions25. JavaScript Hoisting26. JavaScript Built-In Objects27. JavaScript Common Mistakes28. JavaScript Output29. JavaScript Variables30. JavaScript Comparison31. JavaScript Switch Statement32. JavaScript Break33. JavaScript Function Parameters34. JavaScript Use Strict35. JavaScript typeof36. JavaScript Performance37. JavaScript Let38. JavaScript Conditionals39. JavaScript Booleans40. JavaScript Continue41. JavaScript Function Return42. JavaScript toString()43. JavaScript Const44. JavaScript Logical Operators45. JavaScript Control Flow46. JavaScript Function Arguments47. JavaScript Type Conversion48. JavaScript Datatypes49. JavaScript Function Expressions50. JavaScript Destructuring51. JavaScript Arrow Functions

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Functions Study PathAdvanced Functions Study Path