Fix: How to use an array as a closed list of strings in typescript?

 In TypeScript, you can use an array to represent a closed list of strings by specifying the valid string values as elements of the array. Here's how you can create and use such an array:


```typescript

const validColors: string[] = ["red", "green", "blue"];


function getColorName(color: string): string {

  if (validColors.includes(color)) {

    return color;

  } else {

    throw new Error("Invalid color");

  }

}


// Example usage:

try {

  const selectedColor = "red";

  const validColor = getColorName(selectedColor);

  console.log(`Selected color: ${validColor}`);

} catch (error) {

  console.error(error.message);

}

```


In this example:


1. `validColors` is an array that contains a list of valid color strings: "red", "green", and "blue".


2. The `getColorName` function takes a string argument, checks if it exists in the `validColors` array using `includes`, and returns the same string if it's valid. If the input is not in the valid list, it throws an error.


3. In the example usage, we call `getColorName` with a valid color ("red") and then handle the result. If an invalid color is provided, it throws an error.


By using an array in this way, you can create a closed list of valid string values, ensuring that only the specified strings are accepted, and any other values are considered invalid.

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