notes.md

Week 05 Day 2

Topic

• functions

What Are Functions

• code blocks that does a specific thing
• helps avoid repetition in code
• perform same actions with different data

Using Functions

• syntax

  function <functionName> () {
      // do something
  }

• steps

  • declaration
  • invocation/calling

• example

  // function declaration
  function addTwoNumbers(num1, num2) {
    return (res = num1 + num2);
  }
  
  // calling function
  console.log(addTwoNumbers(2, 2));

Functions Inside Object

• example

  var person = {
      name: "rahul choudhary",
      profession: "web developer",
      intro : function () {
          console.log("hello");
      };
    },
  };

Common Methods

• toLowerCase()
• stringName.length()
• stringName.slice(start, end)
• stringName.indexOf("r")
• personName.replace("n", "m")
• stringName.push("element")
• stringName.pop("element")
• numbers.unshift(1, 2, 3...)
• numbers.concat([1, 2, 3...])
• data.hasOwnProperty("name")

Accepting Inputs

• arguments

• parameters

• example

  function addTwoNumbersWithInputs (num1, num2) {
      console.log(num1, num2);
  }
  
  addTwoNumbersWithInputs(3, 4);

Return

• to get output from a function use return keyword
• note - you cannot use multiple return statement

Terms

• mutability and immutablity
• regular expression

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