validateValueOf

Validates that a value exists among the values of a given object or enum.

This helper checks whether a provided value exists in the set of own property values of a target object or TypeScript enum. It never mutates input and never throws.

It uses the isValueOf function internally to perform runtime-safe checks.

Signature

function validateValueOf<T>(
  value: unknown,
  obj: Record<PropertyKey, T>
): T | null

Parameters

Name	Data type	Description
value	unknown	The value to validate.
object	T	The enum or object who values are valid.

Returns

One of:

• The original value if it exists among the object values (T).
• null: If the value does not exist.

Behavior

• Accepts any value for validation.
• Rejects values that are not present among the values in obj.
• Works with both plain objects and TypeScript enums.
• Never throws and never mutates input.

Examples

const obj = { a: 1, b: 2 };

validateValueOf(1, obj) // 1
validateValueOf(2, obj) // 2
validateValueOf(3, obj) // null
validateValueOf("1", obj as unknown as Record<string, unknown>) // null

enum Colors { Red = "RED", Blue = "BLUE" }

validateValueOf("RED", Colors as unknown as Record<PropertyKey, unknown>)   // "RED"
validateValueOf("BLUE", Colors as unknown as Record<PropertyKey, unknown>)  // "BLUE"
validateValueOf("GREEN", Colors as unknown as Record<PropertyKey, unknown>) // null

Notes

• This helper validates values, not keys.
• Use validateKeyOf if you want to validate keys instead of values.
• Ideal for validating enum values, configuration values, or any object’s set of acceptable constants.
• Fully TypeScript-safe and compatible with objects and enums.