Enumerations


const myEnum = { 
   Up : 'Up string',
   Down : 'Down string',
   Right : 'Right string',
   Left : 'Left string'
}

let myValue: number = myEnum.Up;

Returns an array

Object.keys(myEnum) 

Check if a value equals

=== myEnum.Down 

Check if a value is in the enumeration

myEnum.hasOwnProperty('Up');  


Object.Freeze

However it is possible in your code to redefine these constants

myEnum.Up = 'change the text'; 

To prevent the value from being changed we can freeze the enumeration

const myEnum = Object.freeze({ 
   Up : 'Up string',
   Down : 'Down string',
   Right : 'Right string',
   Left : 'Left string'
});

Type Literals

Do not use enums, just use type literals ?

type Colors = 'red | 'blue' | 'green'  


TypeScript Enumerations

At the moment the "enum" keyword has not been added to JavaScript
TypeScript Enumerations



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