Typescript number to float

TypeScript Data Types Tutorial

In this TypeScript tutorial we learn about the different types of data that can be stored in data containers.

We learn the basic types in TypeScript like numbers, booleans, strings, void, null, undefined and any.

What are data types

Data types are the different types of values that can be stored by TypeScript.

The type of a value is checked before the data is stored or manipulated, ensuring that the code will behave as we would exprect it to.

note Although explicit data type declaration is optional in TypeScript, we recommend it in most cases.

TypeScript provides us with the following data types.

• Generics
• Decorators
• Static types
  • Built-in types
    • Number
    • String
    • Boolean
    • Void
    • Null
    • Undefined
    • Never
    • Any
    • Array
    • Tuple
    • Enumeration (enum)
    • Class
    • Interface

    In this tutorial lesson we will briefly discuss some of the built-in static data types in TypeScript.

    The number data type (int/float)

    The number type represents both integers and fractions. That’s to say, whole numbers like 83 or -514 as well as floating point numbers like 3.14 or -781.1.

    The number type uses the number keyword.

      The number type also supports hexadecimal , octal and binary values.

    The boolean data type

    A boolean is a named constant that represents the logical values true and false.

    Booleans are technically numbers themselves because the values true and false map to 1 and 0 respectively.

    The boolean type uses the boolean keyword.

      tip If you come from another programming language like C#, please remember that in TypeScript we write the full word and not just bool.

    The string data type

    A string is an array of Unicode characters combined to form words or sentences. Strings can be wrapped in single or double quotes.

    The string type uses the string keyword.

      If we wrap our strings in double quotes, we can use single quotes inside strings where we need them.

      Otherwise we would need to escape them with the slash symbol.

    The void return type

    The void type is used as a function return type and represents functions that do not return a value.

    The void type uses the void keyword.

    Our function doesn’t return anything, it just prints a message to the console. We give it the void type in the function header to explicitly state that the function doesn’t return a value.

    The null data type

    Null represents the intentional absense of value.

    We typically assign null as value during the coding process when we write code that doesn’t exist yet, but will later.

    The null type uses the null keyword.

     As an example, let’s consider we’re developing a game but it hasn’t been decided yet what the actual number is for the maximum damage a player can do.

    The programmer will set up the value right now as null and fill in the real value later when the number has been decided.

    The undefined data type

    When we declare empty variables, the undefined type is assigned to them until we assign a value to them.

    The undefined type uses the keyword undefined .

    The any type is given when we don’t know what the value will be at runtime.

    When we assign any as a type we essentially opt-out of type checking and let the value pass through compile-time checks.

    It’s especially useful when working with collection types if we know part of the type, but not all of it. It also makes working with existing Javascript easier.

    The any type uses the keyword any .

    • Data types represent the types of data that can be stored.
    • The number type can store integers, hexadecimal, octal, binary and floating point numbers.
    • The boolean type is a named constant that contains two values, true and false.
      • The true and false values also map to 1 and 0 respectively.
      • A string is always wrapped in either double or single quotes.
      • When a string is wrapped in single quotes, special characters must be escaped with a slash operator.

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      TypeScript Number Data Type

      The Typescript number data type stores the numbers as a double-precision 64-bit number The Typescript has two data types to deal with the Numbers. One is a primitive number data type. The other one is BigInt, which is a recent addition. It does not have separate data types like integers, decimal, float as in the other languages. The number is a primitive data type. The Typescript also has a Number object. We also have listed the difference between number Vs Number. The Number object has many properties & methods, which you can make use of and is listed at the end of the article.

      Number Data Type

      The number data type represents all numbers in TypeScript. It also contains three special values i.e. Not A Number ( NaN ), positive infinity and negative infinity. The number is a primitive data type in TypeScript

      There are two ways you can define a primitive number

      Using literal syntax

      Number global function

      Number object

      The Typescript also has the Number object. The Number object is created using the Number constructor i.e by using the new Number() keyword.

      If you do not use the new keyword, then a primitive number is created

      You can check the type of a variable using the typeof keyword.

      number Vs Number

      The number is a primitive data type. It is the one you must use. The primitive data type does not have properties or methods.

      The Number is a wrapper object around number . It is created by using the syntax new Number(value) . The objects have properties & methods.

      You can assign primitive number to Number object, but not the other way around.

      ‘number’ is a primitive , but ‘Number’ is a wrapper object . Prefer using ‘number’ when possible . ts ( 2322 )

      NaN

      The NaN stands for not a number. It is the result of numerical operations, where the result is not a number.

      A non-numeric value as the argument to the Number’s constructor results in NaN .

      You can read more about it from NaN in Typescript tutorial

      Max, Min & Safe Values

      The Typescript number has its limitation regarding Max Value, Safe Value & Min Value that you can use. The Typescript uses the MAX_SAFE_INTEGER, MIN_SAFE_INTEGER, MAX_VALUE & MIN_VALUE to represent these values

      The above limitations are due to the fact that the Javascript stores the numbers as double-precision 64-bit number. Each number can be stored using the total 64-bit memory. Out of 64bits, one is used for the sign, 11 for the exponent and remaining 52 bits are used for the mantissa (significand).

      The max integer that can be stored in 52 bits is 9007199254740991. It is represented by MAX_SAFE_INTEGER & the minimum value is -9007199254740991 and is represented by MIN_SAFE_INTEGER

      Any number above this number will result in a loss of accuracy. For Example, adding 1 & 2 to the MAX_SAFE_INTEGER results in the same value

      You can use the Number.isSafeInteger method to check whether the number is safe.

      The largest number possible to represent using the number data type is 1.7976931348623157e+308 and it is represented by Number.MAX_VALUE . The lowest number is Number.MIN_VALUE .

      The bitwise operators and shift operators operate on 32-bit integers only, so in that case, the max safe integer is 2147483647.

      Infinity

      The Infinity is the property of the global Number object.

      Infinity can result in many ways, for example multiplying Number.MAX_VALUE by 2 results in infinity .

      You can use the Number.isFinite method to verify whether the number is finite.

      Number Properties & Methods

      Properties

      Property	Description
      EPSILON	The value of Number.EPSILON is the difference between 1 and the smallest value greater than 1 that is representable as a Number value, which is approximately: 2.2204460492503130808472633361816 x 10‍−‍16.
      MAX_SAFE_INTEGER	The value of the largest integer n such that n and n + 1 are both exactly representable as a Number value. The value of Number.MAX_SAFE_INTEGER is 9007199254740991 2^53 − 1.
      MAX_VALUE	The value of the largest integer n such that n and n + 1 are both exactly representable as a Number value. The value of Number.MAX_SAFE_INTEGER is 9007199254740991 2^53 − 1.
      MIN_SAFE_INTEGER	The value of the largest integer n such that n and n + 1 are both exactly representable as a Number value. The value of Number.MAX_SAFE_INTEGER is 9007199254740991 2^53 − 1.
      MIN_VALUE	The closest number to zero that can be represented in JavaScript. Equal to approximately 5.00E-324
      NEGATIVE_INFINITY	A value that is less than the largest negative number that can be represented in JavaScript. JavaScript displays NEGATIVE_INFINITY values as -infinity.
      NaN	A value that is not a number. In equality comparisons, NaN does not equal any value, including itself. To test whether a value is equivalent to NaN, use the isNaN function.
      POSITIVE_INFINITY	A value greater than the largest number that can be represented in JavaScript. JavaScript displays POSITIVE_INFINITY values as infinity.

      Methods

      Method	Description
      isFinite	Returns true if passed value is finite. Unlike the global isFinite, Number.isFinite doesn’t forcibly convert the parameter to a number. Only finite values of the type number, result in true.

      @param s — A string to convert into a number.

      Instance Methods

      Method	Description
      toExponential	Returns a string containing a number represented in exponential notation.

      @param locales — A locale string or array of locale strings that contain one or more language or locale tags. If you include more than one locale string, list them in descending order of priority so that the first entry is the preferred locale. If you omit this parameter, the default locale of the JavaScript runtime is used.

      Summary

      The Typescript number is a primitive data type that stores the numbers as double-precision 64-bit number. The Typescript also has Number object, which is a wrapper around the primitive number. It is always suggested to use the primitive number. The Number object provides several properties, methods, etc.

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