Assigning enum type variable using string in TypeScript

How can I dynamically assign a value to a TypeScript enum variable?

Given:

enum options { 'one' = 'one', 'two' = 'two', 'three' = 'three'}
let selected = options.one

I want to set the variable "selected" based on a string value, and the following function accomplishes this:

function setSelected (newOption: string): void {
  switch (newOption) {
    case 'one':
      selected = userThemePreferences.one
      break
    case 'two':
      selected = userThemePreferences.two
      break
    default:
      selected = userThemePreferences. three
      break
  }
}

Is it possible to create a function that remains unaffected by changes in the enum items? Currently, if we add 'four' to our enum, we would need to update the switch statement cases. How can we avoid this scenario?

Answer №1

To convert a string to an enum in TypeScript, you can use the keyof typeof method. The code snippet below demonstrates this conversion:

enum options { 'one' = 'one', 'two' = 'two', 'three' = 'three'}

let selected: options = options.one;
const newOption = "two";

console.log(selected); //prints "one"

selected = options[newOption as keyof typeof options];
// Handle if newOption is not a valid enum string
if(selected === undefined){
    selected = options.three;
}

console.log(selected); //prints "two"

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