export enum r {
  color1 = "Red"
  color2 = "green"
  color3 = "blue"
}

ar = ["color1", "color2"];
ar.map(e => {
  if (r[e as any] !== undefined) {
    return r[e]
  }
})

Above statement giving "Element implicitly has an any type because index expression is not of type number"

export enum r {
  color1 = "Red"
  color2 = "green"
  color3 = "blue"
}

ar = ["color1", "color2"];
ar.map(e => {
  if (r[e as any] !== undefined) {
    return r[e]
  }
})

Above statement giving "Element implicitly has an any type because index expression is not of type number"

• javascript
• typescript
• react-native
• enums

2 Answers 2

You need to type ar with keyof typeof to let TypeScript know your array contains keys from your enum:

export enum r {
  color1 = "Red",
  color2 = "green",
  color3 = "blue",
}

const ar: (keyof typeof r)[] = ["color1", "color2"];
const newVal = ar.map((e) => {
  if (r[e] !== undefined) {
    return r[e];
  }
});

Here is a good in-depth answer about it

You do not have mas after every item in your enum. However, the following is how you can typecast the argument to be type of key of the enum:

export enum r {
color1 = "Red",
color2 = "green",
color3 = "blue",
}

const ar = ["color1","color2"];
const new_ar = ar.filter(e => {
    if (e in r && r[e as keyof typeof r]) 
    {return true;}
    else {return false;}
})

The problem with your approach is you are using map and you need to return in every iteration. What you need is filter.