JavaScript - number methods

revision:

The Number object contains only the default methods that are part of every object's definition.

constructor() : returns the function that created this object's instance. By default this is the Number object.

toExponential() : forces a number to display in exponential notation, even if the number is in the range in which JavaScript normally uses standard notation.

toFixed() : formats a number with a specific number of digits to the right of the decimal.

toLocaleString() : returns a string value version of the current number in a format that may vary according to a browser's locale settings.

toPrecision() : defines how many total digits (including digits to the left and right of the decimal) to display of a number.

toString() : returns the string representation of the number's value.

valueOf() : returns the number's value.

isFinite() : determines whether the passed number is a finite number or not.

isInteger() : determines whether the number passed on as a parameter is an integer or not.

isNaN() : returns true is the number equal to NaN and false if otherwise.

isSafeInteger() : checks whether the number passes in a parameter is a safe integer. A safe integer consists of all integers from -(253–1) to 253–1 (+/-9007199254740991)

parseFloat() : parses the string and returns the very first number it finds.

parseInt() : returns a string that represents the number we passed to it in exponential aka scientific notation.

Examples

code: 
                <div>
                    <p id="numbers1"></p>
                    <p id="numbers2"></p>
                    <p id="numbers3"></p>
                    <p id="numbers4"></p>
                    <p id="numbers5"></p>
                    <p id="numbers6"></p>
                    <p id="numbers7"></p>
                    <p id="numbers8"></p>
                    <p id="numbers9"></p>
                    <p id="numbers10"></p>
                    <p id="numbers11"></p>
                    <p id="numbers12"></p>
                    <p id="numbers13"></p>
                    <p id="numbers14"></p>
                    <p id="numbers15"></p>
                    <p id="numbers16"></p>
                    <p id="numbers17"></p>
                    <p id="numbers18"></p>
                    <p id="numbers19"></p>
                    <p id="numbers20"></p>
                    <p id="numbers21"></p>
                    <p id="numbers22"></p>
                    
        
                </div>
                <script>
                    var x = 9.656;
                    var newX = x.toFixed(0);
                    document.getElementById("numbers1").innerHTML = "toFixed(0) : " + newX;
                    var newX = x.toFixed(2); 
                    document.getElementById("numbers2").innerHTML = "toFixed(2) : " + newX;
                    var newX = x.toFixed(4);  
                    document.getElementById("numbers3").innerHTML = "toFixed(4) : " + newX;
                    var newX = x.toFixed(6);  
                    document.getElementById("numbers4").innerHTML = "toFixed(6) : " + newX;
                    document.getElementById("numbers5").innerHTML = "toFixed()) : " + (typeof(newX))
        
                    var x = 9.656;
                    var newX = x.toPrecision(2);
                    document.getElementById("numbers6").innerHTML = "toPrecision(2) : " + newX;
                    var newX = x.toPrecision(4);  
                    document.getElementById("numbers7").innerHTML = "toPrecision(4) : " + newX;
                    var newX = x.toPrecision(6);  
                    document.getElementById("numbers8").innerHTML = "toPrecision(6) : " + newX;
                    document.getElementById("numbers9").innerHTML = "toPrecision() : " + (typeof(newX));
        
                    function addition(r) {
                      return parseFloat(r) * 2.0;
                    }
                    console.log(addition(2))
                    document.getElementById("numbers10").innerHTML = "parseFloat(2) : " + addition(2);
                    console.log(addition("2"))
                    document.getElementById("numbers11").innerHTML = "parseFloat('2') : " + addition("2");
                    console.log(addition("3.3"))
                    document.getElementById("numbers12").innerHTML = "parseFloat('3.3') : " + addition("3.3");
        
                    var x = true;
                    console.log(Number(x))
                    document.getElementById("numbers13").innerHTML = "Number(x) : " + Number(x);
                    var x = false;
                    document.getElementById("numbers14").innerHTML = "Number(x) : " + Number(x);
                    var x = "999";
                    document.getElementById("numbers15").innerHTML = "Number('999') : " + Number('999');
        
                    function additionA(r) {
                      return parseInt(r) * 2.0;
                    }
                    console.log(additionA(2))
                    document.getElementById("numbers16").innerHTML = "parseInt(2) : " + additionA(2);
                    console.log(additionA("2"))
                    document.getElementById("numbers17").innerHTML = "parseInt('2') : " + additionA("2");
                    console.log(additionA("3.3"))
                    document.getElementById("numbers18").innerHTML = "parseInt('3.3') : " + additionA("3.3");
        
                    const isFinite = Number.isFinite(3); 
                    document.getElementById("numbers19").innerHTML = "isFinite(3) : " + isFinite;
        
                    const isInteger = Number.isInteger(3.3); 
                    document.getElementById("numbers20").innerHTML = "isInteger(3.3) : " + isInteger;
        
                    const isNaN = Number.isNaN(100); 
                    document.getElementById("numbers21").innerHTML = "isNaN(100) : " + isNaN;
        
                    const isSafeInteger = Number.isSafeInteger(100); 
                    document.getElementById("numbers22").innerHTML = "isSafeInteger(100) : " + isSafeInteger;
                </script>