@multitrack/vue

Vue 3 bindings for @multitrack/core — a scroll-driven animation engine with a multi-track timeline architecture.

Install

npm install @multitrack/core @multitrack/vue

Quick start

<script setup lang="ts">
import { MultitrackProvider, ScrollContainer, FixedStage, Show, useStep } from "@multitrack/vue";
import type { StepConfig } from "@multitrack/core";

const config: StepConfig[] = [
  { name: "intro", duration: 3, track: "main", easing: "linear" },
  { name: "feature", duration: 5, track: "main" },
  { name: "outro", duration: 3, track: "main", easing: "linear" },
];
</script>

<template>
  <MultitrackProvider :config="config">
    <ScrollContainer>
      <FixedStage>
        <Show when="intro">
          <IntroSection />
        </Show>
        <Show when="feature">
          <FeatureSection />
        </Show>
      </FixedStage>
    </ScrollContainer>
  </MultitrackProvider>
</template>

<!-- IntroSection.vue -->
<script setup lang="ts">
import { useStep } from "@multitrack/vue";

const { opacity } = useStep("intro");
</script>

<template>
  <div :style="{ opacity: opacity, transform: `translateY(${(1 - opacity) * 40}px)` }">
    <h1>Welcome</h1>
  </div>
</template>

API

<MultitrackProvider>

Wraps your app and creates the timeline instance. All composables and components must be used within this provider.

<MultitrackProvider :config="config" :breakpoints="breakpoints" devtools>
  <slot />
</MultitrackProvider>

Composables

useStep(name)

Returns { opacity, isActive } as Vue computed refs for a single step.

useOpacities()

Returns a computed ref containing an Opacities record ({ [stepName]: number }) for all steps.

useScrollProgress()

Returns { scrollPercentage, currentStep, totalSteps } as computed refs.

useTimeline()

Returns the underlying Timeline instance for advanced use cases.

Components

<ScrollContainer>

The scrollable container that drives the timeline. Renders a <div> with the correct scroll height.

<FixedStage>

A fixed-position overlay inside ScrollContainer for content that stays in the viewport while scrolling.

<Show when="stepName">

Conditionally renders children when the named step is active (opacity > 0).

DevTools

Enable the Chrome DevTools integration by passing the devtools prop to the provider:

<MultitrackProvider :config="config" devtools>
  <slot />
</MultitrackProvider>

This exposes timeline state to the @multitrack/devtools Chrome extension, giving you a live timeline inspector with playhead visualization, active step opacities, and an event log.

Full example with useStep()

For fine-grained control over individual steps, use the useStep() composable to get { opacity, isActive } computed refs and drive animations directly:

<script setup lang="ts">
import { MultitrackProvider, ScrollContainer, FixedStage, Show } from "@multitrack/vue";
import type { StepConfig } from "@multitrack/core";
import IntroSection from "./IntroSection.vue";
import FeatureSection from "./FeatureSection.vue";
import Caption from "./Caption.vue";

const config: StepConfig[] = [
  { name: "intro", duration: 3, track: "main", easing: "linear" },
  { name: "feature", duration: 5, track: "main" },
  { name: "outro", duration: 3, track: "main", easing: "linear" },

  // Independent text track — overlaps freely with main
  { name: "buffer", duration: 4, track: "text" },
  { name: "caption", duration: 3, track: "text" },
];
</script>

<template>
  <MultitrackProvider :config="config" devtools>
    <ScrollContainer>
      <FixedStage>
        <Show when="intro">
          <IntroSection />
        </Show>
        <Show when="feature">
          <FeatureSection />
        </Show>
        <Show when="caption">
          <Caption text="Tracks are independent." />
        </Show>
      </FixedStage>
    </ScrollContainer>
  </MultitrackProvider>
</template>

<!-- IntroSection.vue -->
<script setup lang="ts">
import { useStep } from "@multitrack/vue";

const { opacity } = useStep("intro");
</script>

<template>
  <div :style="{ opacity: opacity, transform: `translateY(${(1 - opacity) * 40}px)` }">
    <h1>Welcome</h1>
  </div>
</template>

License

MIT