Coding Cheatsheet

Javascript has only one type of number. Numbers can be written with or without decimals. Numbers are not written with any quotations, otherwise it would be a string.

    var x = 57;
    x.typeOf(); -> number.

    var y = "567"
    y.typeOf(); -> string.

Some things that you should note regarding JS numbers are:
NaN - a JS reserved keyword indicating the result is 'Not a Number'
E.g. var x = 500/"word" will return NaN.

If you divide by 0, JS will always return 'infinity'. The data type of infinity is number.

Number Methods.

Javascript has different methods that can be used on numbers. Some are listed below

parseInt() parses a string and returns an integer.

parseFloat() takes a string and returns a floating-point number.

toString() converts a number to a string e.g. var myNum = 85; myNum.toString(); // '85'

toFixed(2) converts a number to a string, but keeping only two decimals.

isFinite(number) checks if the value in parenthesis is an actual number.

isInteger(number) checks if the value in parenthesis is an integer.

isNaN(number) checks if the value in parenthesis is NaN.

Math Methods.

Javascript has different math methods that can be used on numbers. Some are listed below

math.floor rounds down the number. 2.1 will be 2.

math.ceil rounds up the number. 1.1 will be 2.

math.round rounds to the nearest integer. It means 1.4 will be 1, but 1.6 will be 2.

math.trunc removes the decimal part of the number. 4.5 will be 4.

math.sqrt returns the square root of the number.

math.cbrt returns the cube root of the number.

math.random returns a random number between 0 (inclusive) and 1 (exclusive).