Boolean

Boolean fields use x.boolean() for boolean values. Recognises common truthy/falsy strings ("yes", "no", "true", "false", "1", "0", etc.).

x.boolean().label("Active")

columnNameAliases

Adds alternate CSV header names for this field.

.columnNameAliases(aliases: string[])

• aliases lists header names that should map to this schema key.
• Aliases are used during column matching alongside the field key and label. They do not change the output object key.

label

Sets the user-facing label shown in the importer.

.label(text: string)

• text sets the label text.

description

Sets help text shown below the field.

.description(text: string)

• text sets the description text.

optional

Allows the field to be empty.

.optional()

• Empty optional values are delivered as null.
• The row object still includes the field key, e.g., { active: null }.

default

Available after .optional().

.default(defaultValue: unknown | (() => unknown | Promise<unknown>))

• defaultValue can be a static value or a function used when the field is empty.
• Defaults apply to missing values, null, empty strings, and whitespace-only strings.
• When a default is used, it is returned directly instead of validating or refining the empty value.