CODEWITHSUNDEEP
typescript
Tom
Tom

Reputation: 1565

Conditional property for typescript type/object

Let's say I have a recipe ingredient type that looks like this

export type RecipeIngredient = {
  name: string;
  quantity: Number | string;
  measurement: "grams" | "mililitres" | "custom";
};

Example

const potatoes: RecipeIngredient = { name: 'potatoes', quantity: 100, measurement: 'grams' }

which is fine, but I also want to have the quantity as a string only when the measurement is custom. Is this possible?

Correct example

const rosemary: RecipeIngredient = { name: 'rosemary', quantity: 'a handful', measurement: 'custom' }

What I want to be invalid

const fish: RecipeIngredient = { name: 'fish', quantity: '100g', measurement: 'grams' }

Upvotes: 1

Views: 35

Answers (1)

hackape
hackape

Reputation: 19947

export type RecipeIngredient = {
  name: string;
  quantity: Number;
  measurement: "grams" | "mililitres";
} | {
  name: string;
  quantity: string;
  measurement: "custom";
};

Upvotes: 2

Related Questions