Data types conversions in javascript

Number conversions

1. String to Number conversion

   When we want to convert a String to a number we use Number() function

    let goalsScored="4";
    let goalsScoredInNum= Number(goalsScored)  //Output: 4
    //if we check type of goalsScoredInNum it will show as Number
    console.log(typeof goalsScoredInNum);
   

2. Invalid String to Number conversion

   When we try to convert the string which cannot be converted into a number the converted value will be NaN i.e, not a number

    let scoreSheet = "43 Messi"
    let scoreSheetInNum= Number(scoreSheet )  //Output: NaN
    //if we check type of scoreSheetInNum it will show as Number
    console.log(typeof goalsScoredInNum);
   

3. Conversion of Null to Number

   When we try to convert null to a number the converted value turns out to be zero

    let nullValue= null //this value is null and cannot be converted to number
   
    console.log(typeof nullValue); //when we check type it shows Object
   
    let ConvertedValue= Number(nullValue) //we try to convert it into number
   
    console.log(typeof ConvertedValue); //when we check type of converted value it shows type as number
   
    console.log(ConvertedValue); //Output: 0 when we console log the actual value it shows as 0 so null converted to number is 0
   

4. Conversion of undefined variable to Number

   Direct conversion of any undefined number to a number, will result in NaN however when we check the type of converted variable it shows as Number

    let undefinedVal; //undefined variable
    let convertedUndefinedVal = Number(undefinedVal)
    console.log(convertedUndefinedVal); //Output: NaN
    console.log(typeof convertedUndefinedVal); //Output: Number
   

5. Conversion of Boolean to Number

   When we try to convert a boolean to a Number then true value will result in 1 and false value will result in 0

    let booleanVariable = true; //Boolean variable true
    let convertedBooleanVal = Number(booleanVariable)
    console.log(convertedBooleanVal); //Output: 1
    console.log(typeof convertedBooleanVal); //Output: Number
   
    let booleanVariable2 = false; //Boolean variable false
    let convertedBooleanVal2 = Number(booleanVariable2)
    console.log(convertedBooleanVal2); //Output: 0
    console.log(typeof convertedBooleanVal2); //Output: Number
   

Boolean Conversions

1. String to Boolean

   When we try to convert String to boolean for any string the converted output will be true except for the empty string for empty string the converted output will be false as shown below

    //converting string to boolean
    let StringVal = "Uday" //String 
    let boolVal = Boolean(StringVal); //converting a String to boolean
    console.log(typeof boolVal); //type of converted value it shows boolean
    console.log(boolVal); //Output: true
    let StringVal2 = "" //emptyString
    let boolVal2 = Boolean(StringVal2); // converting an empty string to boolean
    console.log(typeof boolVal2); //type of converted value it shows boolean
    console.log(boolVal2); //Output: false
   

2. Number to Boolean

   When we try to convert a number to boolean it convert it to true for any number except for the zero for zero only the converted output will be false as shown below

    //converting +ve Number to boolean
    let NumberVal1 = 4; // +ve number value 
    let BoolNumVal1 = Boolean(NumberVal1); // converting number to boolean
    console.log(typeof BoolNumVal1); //shows type as boolean
    console.log(BoolNumVal1); //Output: true 
   
    //converting 0 to boolean
    let NumberVal2 = 0; // 
    let BoolNumVal2 = Boolean(NumberVal2); // converting number to boolean
    console.log(typeof BoolNumVal2); //shows type as boolean
    console.log(BoolNumVal2); //Output: false
   
    //converting -ve Number to boolean
    let NumberVal3 = -3; // 
    let BoolNumVal3 = Boolean(NumberVal3); // converting number to boolean
    console.log(typeof BoolNumVal3); //shows type as boolean
    console.log(BoolNumVal3); //Output: true
   

3. Null to Boolean

   When we try to convert the Null value to a boolean the converted value will be false

    let nullValue = null;
    let boolValue = Boolean(nullValue); 
    console.log(boolValue) //Output: false
    console.log(typeof boolValue)//Output: Boolean
   

4. undefined to boolean

   When we try to convert the undefined value to a boolean the converted value will be false

    let undefinedValue = undefined;
    let boolValue = Boolean(undefinedValue); 
    console.log(boolValue) //Output: false
    console.log(typeof boolValue)//Output: Boolean
   

String Conversions

1. Number to String Using toString() method

   We can convert Number to string using the toString method as shown below

    let score = 23;
    //converting the score to String using toString method
    let scoreInString = score .toString();
    console.log(scoreInString); // Output: "23"
    //if we check typeOf scoreInString it will give output as String
    console.log(typeof scoreInString)
   

2. Number to String Using String function

   We can convert Number to string using the String method as shown below

    let score = 23;
    //converting the score to String using toString method
    let scoreInString = String(score);
    console.log(scoreInString); // Output: "23"
    //if we check typeOf scoreInString it will give output as String
    console.log(typeof scoreInString)
   

3. Boolean to String

   When we convert boolean to String for boolean true the converted String would be "true" and for boolean false the converted String would be "false" as shown below

    let isTrue=true //bool value true
    let StringVal= String(isTrue); //converting it to string
    console.log(typeof StringVal); // printing type of StringVal: string
    console.log(StringVal); //printing value of StringVal: "true" 
   
    let isFalse=false //bool value false
    let StringVal2= String(isFalse); //converting it to string
    console.log(typeof StringVal2); // printing type of StringVal2: string
    console.log(StringVal2); //printing value of StringVal2: "false"
   

4. Undefined to String

   When we try to convert undefined to String the converted value would be "undefined" and the type of the converted value will be String

    let undefinedValue = undefined;
    console.log(undefinedValue);
    let stringValue = String(undefinedValue); 
    console.log(stringValue);//Output: undefined
    console.log(typeof stringValue);//Output String
   

5. Null to String

   When we try to convert null to String the converted value would be "null" and the type of the converted value will be String

    let nullValue = null;
    console.log(nullValue);
    let stringValue = String(nullValue); 
    console.log(stringValue);//Output: undefined
    console.log(typeof stringValue);//Output String