CODEWITHSUNDEEP
reactjstypescript
MeltingDog
MeltingDog

Reputation: 15414

How do I 'cast' someting in TypeScript?

I am new to React/Typescript. I have a function that takes a number and outputs a string, as such:

const getCurrentLevel = (wordCount: number): Level => {
  if (wordCount <= 3) {
    return 'Low';
  }

  if (wordCount <= 6) {
    return 'Med';
  }

  return 'High';
};

I then call this function below:

let helperLevel = getCurrentLevel(numWords);

And pass that to another component:

<helperText level={helperLevel} />

All this works fine, but I get a warning on compilation.

Cannot find name 'Level'.

On the line:

const getCurrentLevel = (wordCount: number): Level => {

I'm not sure what this means or now to fix it. As I understand, I must 'cast' this as "Level" as above. But I am not sure how to go about fixing this or what the error means.

Can anyone point me in the right direction?

Upvotes: 0

Views: 47

Answers (1)

kyun
kyun

Reputation: 10264

type Level = 'Low' | 'Med' | 'High'

declare this line.

Added

(wordCount: number): Level => { } means it has one parameter as number type, it returns Level type. In your case, you return 'High', 'Low' and 'Med' you can declare like above that.

Upvotes: 2

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