@prismicio/types-internal/src/validators/NumberRange.ts

Prismic types for Custom Types and Prismic Data

import * as t from "io-ts"

import { Number } from "./BasicTypes"

/**
 * Creates a custom runtime type for validating that a number falls within a specified range.
 *
 * @param min - The minimum value of the range.
 * @param max - The maximum value of the range.
 * @param fieldName - The name of the field being validated (used in error messages).
 * @returns A runtime type representing the number range validation.
 *
 *  * @example
 * // Creating a custom runtime type for age validation
 * const AgeType = numberInRange(18, 99, 'Age');
 *
 * // Valid age
 * const validAgeResult = AgeType.decode(25);
 * if (t.isRight(validAgeResult)) {
 *   console.log('Valid age:', validAgeResult.right); // Output: Valid age: 25
 * } else {
 *   console.error('Invalid age:', t.left(validAgeResult).map(t.reporter.report));
 * }
 *
 * @example
 * // Invalid age
 * const invalidAgeResult = AgeType.decode(15);
 * if (t.isRight(invalidAgeResult)) {
 *   console.log('Valid age:', invalidAgeResult.right);
 * } else {
 *   console.error('Invalid age:', t.left(invalidAgeResult).map(t.reporter.report));
 * }
 */
export default (min: number, max: number, fieldName: string) =>
	Number.pipe(
		new t.Type<number, number, number>(
			"numberInRange",
			(u: unknown): u is number => Number.is(u),
			(u: number, context) => {
				if (u > max || u < min) {
					return t.failure(
						u,
						context,
						`${fieldName} must be a number between ${min} and ${max}`,
					)
				}
				return t.success(u)
			},
			t.identity,
		),
	)