Represents a schema issue produced when the runtime type of the input does not match the type expected by the schema (e.g. got null when string was expected).

When to use

Use when you need to detect basic type mismatches, such as a wrong primitive or null where an object was expected.

Details

• ast is the schema node that expected a different type.
• actual is Option.some(value) when the input was present, or Option.none() when no value was provided.
• The default formatter renders this as "Expected <type>, got <actual>".

Example (Formatting output)

import { Schema } from "effect"

try {
  Schema.decodeUnknownSync(Schema.String)(42)
} catch (e) {
  if (Schema.isSchemaError(e)) {
    console.log(String(e.issue))
    // "Expected string, got 42"
  }
}