Create a definition for the keys type of an object based on an array

Question

Create a definition for the keys type of an object based on an array

I am looking for a way to dynamically assign symbols from an array called TYPES_ARR as keys in the variable TYPES_GENERATED. I want each key in TYPES_GENERATED to have a corresponding symbol value.

const TYPES_ARR = [
  'HttpClient',
  'Parser'
]
const TYPES_GENERATED = {}

TYPES_ARR.forEach(i => {
  TYPES_GENERATED[i] = Symbol.for(i)
})

Instead of explicitly defining the types like below:

const TYPES_GENERATED: {
  HttpClient: symbol
  Parser: symbol
} = {}

I found this solution on this link.

Is there a more dynamic way to achieve this using the latest version of TypeScript?

arrays typescript object types typescript-typings

Answer 1

Answer №1

One approach to optimize this code is by utilizing a const assertion to enable the compiler to monitor the specific string literal values within TYPES_ARR. After that, it's recommended to confirm that TYPES_GENERATED represents a mapped type (for instance, using the predefined Record<K, V>) with keys derived from the elements of TYPES_ARR and values set as type symbol:

const TYPES_ARR = ["HttpClient", "Parser"] as const;
const TYPES_GENERATED = {} as Record<typeof TYPES_ARR[number], symbol>;
TYPES_ARR.forEach(i => {
  TYPES_GENERATED[i] = Symbol.for(i);
});

Hopefully, this suggestion proves useful for your implementation. Best of luck!

Direct link to code sample

Answer 2

One approach to optimize this code is by utilizing a const assertion to enable the compiler to monitor the specific string literal values within TYPES_ARR. After that, it's recommended to confirm that TYPES_GENERATED represents a mapped type (for instance, using the predefined Record<K, V>) with keys derived from the elements of TYPES_ARR and values set as type symbol:

const TYPES_ARR = ["HttpClient", "Parser"] as const;
const TYPES_GENERATED = {} as Record<typeof TYPES_ARR[number], symbol>;
TYPES_ARR.forEach(i => {
  TYPES_GENERATED[i] = Symbol.for(i);
});

Hopefully, this suggestion proves useful for your implementation. Best of luck!

Direct link to code sample

Create a definition for the keys type of an object based on an array

Answer №1

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