Recipes
Validate Related Fields Before Saving
Merge partial updates and reject invalid cross-field combinations.
Collection beforeChange hooks can validate the complete logical document even when an update contains only one changed field.
Reject invalid combinations of field values before they reach the database.
Use this when
- validate fields before saving
- make sure an end date is after the start date
- reject invalid form submissions
- validate multiple fields together
Dyrected concepts
beforeChange, validation, throw to abort
Additional packages: No additional packages.
Complete recipe
This is the canonical source compiled and behavior-tested by @dyrected/knowledge.
import { defineCollection, defineDateTimeField, defineTextField } from "@dyrected/core";
export const Events = defineCollection({
slug: "events",
hooks: {
beforeChange: [
({ data, doc }) => {
const startsAt = data.startsAt ?? doc?.startsAt;
const endsAt = data.endsAt ?? doc?.endsAt;
const start = startsAt ? new Date(startsAt) : undefined;
const end = endsAt ? new Date(endsAt) : undefined;
if (start && Number.isNaN(start.getTime())) {
throw new Error("The event start time must be a valid date.");
}
if (end && Number.isNaN(end.getTime())) {
throw new Error("The event end time must be a valid date.");
}
if (start && end && end <= start) {
throw new Error("The event end time must be after its start time.");
}
return data;
},
],
},
fields: [
defineTextField({ name: "title", label: "Title", required: true }),
defineDateTimeField({
name: "startsAt",
label: "Starts at",
required: true,
}),
defineDateTimeField({
name: "endsAt",
label: "Ends at",
required: true,
}),
],
});Decisions and cautions
- Merge incoming values with the existing document before comparing fields on partial updates.
- Validate that parsed dates are valid before comparing them.
- Return the original patch after validation; returning a merged document can accidentally overwrite concurrent values.
- Use stable application error codes when clients need localized or field-specific messages.
Use field validation when one value can be checked independently. Use a collection hook when correctness depends on siblings or the previous document.