In this article, we will learn How to Convert an enum into an array in Typescript with some examples.

Let’s get started,

Enums As we have discussed, define a set of named constants that exist at runtime as real objects.

Convert numeric enum into an array

To convert a numeric enum into an array we need to use the “Object.values” with the filter function

Let’s have an example

enum gender{
    Male,
    Female,
    Others
}
console.log(Object.values(gender));

When we run this example we will get this result.

> tsc enumtoarray.ts 
> node enumtoarray.js

[ 'Male', 'Female', 'Others', 0, 1, 2 ]

Suppose if we need to filter out only the numeric value then we have to use the filter function.

Like so,

enum gender{
    Male,
    Female,
    Others
}
console.log(Object.values(gender).filter(val=>isNaN(Number(val))));
 

If we need to filter out only the string value.

enum gender{
    Male,
    Female,
    Others
}

console.log(Object.values(gender).filter(val=>!isNaN(Number(val))));

Here is the result:

[ 'Male', 'Female', 'Others' ]
[ 0, 1, 2 ]

Convert a string enum into an array

To convert a string enum into an array we have to use the Object.values or  Object.key functions

Let’s have an example

enum department{
    CS = 'Computer Science Engg',
    Mech = 'Mechanical Engineering',
    EC = 'Electronic and Communication Engg',
    CV = 'Civil Engineering'
}

console.log(Object.keys(department));
console.log(Object.values(department));

Here is the output:

[ 'CS', 'Mech', 'EC', 'CV' ]
[
  'Computer Science Engg',
  'Mechanical Engineering',
  'Electronic and Communication Engg',
  'Civil Engineering'
]

Converting an Enums Key-value pair into an array

To transform an enum into an array of key-value pairs, we need to use the Object.entries() Method with applying a filter function to remove any pairs where the value is not a number.

const Gendernum : [string,number][]=Object.entries(gender)
.filter(([key,value])=> typeof value === 'number')
.map(([key,value])=> [key,value as number]);

console.log(Gendernum);

Result:

[ [ 'Male', 0 ], [ 'Female', 1 ], [ 'Others', 2 ] ]

enum department{
    CS = 'Computer Science Engg',
    Mech = 'Mechanical Engineering',
    EC = 'Electronic and Communication Engg',
    CV = 'Civil Engineering'
}
export const gendermodel:{
    value: string;
    key : string;
}[]=Object.entries(department)
.map(([key,value])=>({key,value}));

console.log(gendermodel);

Result:

[
  { key: 'CS', value: 'Computer Science Engg' },
  { key: 'Mech', value: 'Mechanical Engineering' },
  { key: 'EC', value: 'Electronic and Communication Engg' },
  { key: 'CV', value: 'Civil Engineering' }
]

More Articles – How to Create a Multi-Select Dropdown List in Angular

The post TypeScript Enum | How to Convert Enum into an Array in Typescript appeared first on Tech Insights.