Pretty

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Generating Pretty Printers

The Pretty.make function is designed for creating pretty printers that output a formatted string representation of values according to a given schema.

Example

ts
import { Pretty, Schema } from "@effect/schema"
 
const Person = Schema.Struct({
  name: Schema.String,
  age: Schema.Number
})
 
const PersonPretty = Pretty.make(Person)
 
// returns a string representation of the object
console.log(PersonPretty({ name: "Alice", age: 30 }))
/*
Output:
'{ "name": "Alice", "age": 30 }'
*/
ts
import { Pretty, Schema } from "@effect/schema"
 
const Person = Schema.Struct({
  name: Schema.String,
  age: Schema.Number
})
 
const PersonPretty = Pretty.make(Person)
 
// returns a string representation of the object
console.log(PersonPretty({ name: "Alice", age: 30 }))
/*
Output:
'{ "name": "Alice", "age": 30 }'
*/

Customizing Pretty Printer Generation

You can tailor the output of the pretty printer by using the pretty annotation within your schema definitions.

Example

ts
import { Pretty, Schema } from "@effect/schema"
 
const schema = Schema.Number.annotations({
  pretty: (/**typeParameters**/) => (value) => `my format: ${value}`
})
 
console.log(Pretty.make(schema)(1)) // my format: 1
ts
import { Pretty, Schema } from "@effect/schema"
 
const schema = Schema.Number.annotations({
  pretty: (/**typeParameters**/) => (value) => `my format: ${value}`
})
 
console.log(Pretty.make(schema)(1)) // my format: 1

In this setup, the pretty annotation takes any type parameters provided (typeParameters) and formats the value into a string.