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Version: 0.3.0

Virtual Fields

A virtual field is a purely input field whose value may or may not be provided at creation, used to trigger a change in one or more fields that depend on it.

  • It must have one or more dependent fields depending on it.
  • It must have a validator.
  • It may also have a re-validator.
  • It may have an alias - a different field name on the input struct, used in place of the actual field name (only allowed if the corresponding output field is a dependent field that directly depends on this virtual field).
  • It may have a sanitizer.
  • It may leverage ignore, ignore_init and ignore_update provision rules.
  • It may have on_failure and on_success event handlers.

Example​

virtual_field is a virtual input field. The output dependent uses its value when provided, otherwise it falls back to a default. The dependent field declares its dependency with .depends_on(...):

use std::{future::ready, sync::LazyLock};
use ivo::{dependent_field, virtual_field, IvoContext, IvoInputStruct, IvoModel, IvoStruct};

const DEFAULT_DEPENDENT: &str = "DEFAULT_DEPENDENT_VALUE";

type Ctx = IvoContext<DataInput, Data>;

#[derive(Clone, Debug, PartialEq, IvoInputStruct)]
struct DataInput {
    pub virtual_field: String,
}

#[derive(Debug, Clone, PartialEq, IvoStruct)]
struct Data {
    pub dependent: String,
}

static MODEL: LazyLock<IvoModel<DataInput, Data>> = LazyLock::new(|| {
    IvoModel::new(
        |f| {
            f.field(virtual_field("virtual_field").validate(|v: String, _, _| ready(Ok(Some(v)))))
                .field(
                    dependent_field("dependent")
                        .default(DEFAULT_DEPENDENT.to_string())
                        .depends_on(["virtual_field"])
                        .resolve(|ctx: Ctx, _| {
                            ready(
                                ctx.input()
                                    .virtual_field
                                    .clone()
                                    .unwrap_or_else(|| ctx.values().dependent.clone()),
                            )
                        }),
                )
        },
        |o| o,
    )
});

Examples​