tests.Cost — Kuito Documentation

Usage

Add an interaction budget

This type is used by tests.costOf

tsx

import { Pressable, Text, signal } from 'kuito';
import { costOf, press, render, screen, test } from 'kuito/tests';

function Like() {
  const liked = signal(false);
  return (
    <Pressable onPress={() => (liked.value = !liked.value)} opacity={liked.value ? 1 : 0.6}>
      <Text>Like</Text>
    </Pressable>
  );
}

test('a like lays nothing out', async () => {
  await render(<Like />);

  const cost = await costOf(() => press(screen.getByText('Like')));

  cost.toStayWithin({ layoutPasses: 0, measureCalls: 0, viewsCreated: 0 });
});

Type declaration

export interface Cost extends Readonly<Counts> {
  /** Throws, naming every counter over `budget`, when the cost exceeds it. */
  toStayWithin(budget: CostBudget): void;
}

Members 14

Name	Type	Required	Description
`toStayWithin`	`(budget: CostBudget) => void`	Yes	Throws, naming every counter over `budget`, when the cost exceeds it.
`recordsApplied`	`number`	Yes	Records of the batches applied, the UI thread's prop writes included.
`propWrites`	`number`	Yes	—
`wastedPropWrites`	`number`	Yes	Prop writes of the value the view already had.
`layoutPasses`	`number`	Yes	Layouts that computed at least one node.
`wastedLayoutPasses`	`number`	Yes	Layout passes after which no box changed.
`nodesLaidOut`	`number`	Yes	Nodes the engine computed rather than took from its cache.
`nodesFramed`	`number`	Yes	Boxes the renderer took from a pass.
`wastedFrames`	`number`	Yes	Boxes taken unchanged.
`measureCalls`	`number`	Yes	Leaves measured: each one a miss of the engine's measure cache.
`wastedMeasures`	`number`	Yes	Measures that answered what the leaf measured before it was marked dirty.
`uiEntries`	`number`	Yes	Calls into the UI-thread kernel: operations received, events, frames.
`wastedUiEntries`	`number`	Yes	Events the UI-thread kernel had no handler for.
`viewsCreated`	`number`	Yes	Views made with a native view: a flattened node has none.

toStayWithin — method signatures

Signatures

(budget: CostBudget): void

Parameters

Name	Type	Required	Description
`budget`	`Partial<Counts>`	Yes	—

Returns

void

Generated from the public TypeScript declarations: signatures, props and defaults come from the checked source, descriptions from its JSDoc. No defaults are invented.