Discount

On this page

An amount off a price, or a percentage off it.

Use it for promotions and vouchers. money.apply_discount takes one off a Price.

Shape

One of these, each with its own fields:

Variant	Field	Type	Required?
`Discount.amount_off`	`amount`	`Money`	Yes
`Discount.percentage_off`	`percentage`	`Percentage`	Yes

example

Discount.percentage_off { percentage: 20% }

An object of its variant's name, as tag, and the variant's fields, in a request, a response or json.write:

json

{"tag":"amount_off","amount":{"amount":500,"currency":"GBP"}}{"tag":"percentage_off","percentage":"20%"}{"tag":"percentage_off","percentage":"12.5%"}

Text form, storage, how it is shown, and operations

Discount is in the group Money and banking, and has been in Jadpo since 0.1.0.

It has no single text form, so text.from and text.parse don't take it.

It is stored in 4 columns, each named for the field, _ and its suffix. This is {"tag":"percentage_off","percentage":"20%"}:

text.format(value, locale:) shows it to people in their locale.

With locale: Locale.en_gb:

Value	Shown
`{"tag":"amount_off","amount":{"amount":500,"currency":"GBP"}}`	`£5.00`
`{"tag":"percentage_off","percentage":"20%"}`	`20%`
`{"tag":"percentage_off","percentage":"12.5%"}`	`12.5%`

money.apply_discount(price: Price, discount: Discount) -> Price: price with discount taken off its amount, keeping whether it includes tax: an amount off in the price's currency, or that percentage of the amount, rounded half to even to a minor unit, so 15% off £10.05 is £1.51 off. More off than the price leaves nothing. It fails with currency_mismatch for an amount off in another currency.

It also takes text.format, json.read, json.write and ==. How every standard type behaves says how they work.

Markdown for agents: /docs/types/type-discount.md.Built from Jadpo main at aee2e8f.