Yunfei He
c05cb5df36
A bare `measureElement()` called inside `watchPostEffect` reads layout BEFORE
the commit scheduler's post-flush `calculateLayout` runs, so it returns an
uncomputed value (NaN for computed dimensions), not the current size. The JSDoc
previously recommended that exact broken call site.
Align the guidance to vue-tui's real post-flush timing: defer the read with
`nextTick(() => measureElement(ref.value))` — the pattern `useBoxMetrics` itself
uses — or read from an input/timer callback that fires after a flush; prefer
`useBoxMetrics` for reactive metrics. Also correct the stale claim that a
pre-layout read returns `{0,0}` (it returns NaN for an attached-but-uncomputed
node; `{0,0}` is only the detached case).
Adds a characterization test pinning bare-watchPostEffect = NaN vs
nextTick = real width (80), guarding against regressing to the old advice.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
@vue-tui/runtime
Early stage — under active development. Bug reports welcome, but not recommended for production use yet.
Vue 3 terminal renderer with Yoga flexbox layout — build rich TUI apps with the same component model you use on the web.
Why
- Vue SFC & JSX —
<template>, TSX, or render functions — your choice - Yoga flexbox — the same layout engine behind React Native, not a CSS-subset hack
- Built-in input system — keyboard handling, focus management, Tab navigation
- Terminal-native — renders directly to stdout, purpose-built for CLI tools and AI agent interfaces
@vue-tui/runtime is a terminal platform renderer parallel to @vue/runtime-dom, comparable to React Ink but adapted for Vue's reactivity model.
Install
npm install @vue-tui/runtime vue
Quick Start
// src/main.ts
import { createApp } from "@vue-tui/runtime";
import App from "./app.vue";
createApp(App).mount();
<!-- src/app.vue -->
<script setup lang="ts">
import { shallowRef } from "vue";
import { Box, Text, useInput } from "@vue-tui/runtime";
const count = shallowRef(0);
useInput((input) => {
if (input === "+") count.value++;
if (input === "-") count.value--;
});
</script>
<template>
<Box>
<Text>Count: </Text>
<Text bold color="green">{{ count }}</Text>
<Text dimColor> (+/- to change)</Text>
</Box>
</template>
Components
| Component | Description |
|---|---|
<Box> |
Flexbox container — direction, wrap, align, justify, gap, padding, margin, borders, background |
<Text> |
Styled text — color, bold, italic, underline, strikethrough, dimColor, wrap/truncate modes |
<Spacer> |
Expands to fill available space (flex-grow: 1) |
<Newline> |
Inserts line breaks (configurable count) |
<Static> |
Renders a list of items once, above the redrawn region |
<Transform> |
Applies a string transform function to each rendered line |
Composables
| Composable | Description |
|---|---|
useInput(handler, opts?) |
Keyboard input — (input, key) with modifier and arrow key detection |
useFocus(opts?) |
Component-level focus — returns { isFocused, focus } |
useFocusManager() |
App-level focus — focusNext(), focusPrevious(), focus(id) |
useApp() |
App lifecycle — { exit(error?), waitUntilRenderFlush() } |
useTerminalSize() |
Reactive terminal dimensions — { columns, rows } |
useAnimation(opts?) |
Frame-based animation loop — returns { frame, time, delta, reset } |
useBoxMetrics(ref) |
Reactive layout metrics — { width, height, left, top, hasMeasured } |
measureElement(node) |
Imperative read of computed { width, height } from a yoga node |
useCursor() |
Control terminal cursor visibility |
usePaste(handler, opts?) |
Handle clipboard paste events |
useStdin() |
Access stdin stream and raw mode control |
useStdout() |
Write directly to stdout |
useStderr() |
Write directly to stderr |
App Lifecycle
import { createApp } from "@vue-tui/runtime";
// Fire and forget (most common):
createApp(App).mount();
// Wait for the app to exit:
const app = createApp(App);
app.mount();
await app.waitUntilExit();
// Custom streams (for testing):
createApp(App).mount({ stdout, stdin, stderr });
Links
- vue-tui — monorepo root
@vue-tui/cli— dev server with HMR@vue-tui/testing— test harness for terminal components
License
MIT