Fetch composition

Compares one structured origin, sequential composition, and explicit portable concurrency in one project. Comments in the handler mark each form.

Workflow

pulse doctor
pulse inspect
pulse test
pulse dev
pulse build

The documented test result below is executed by the documentation gate.

pulse test --json

{
  "status": "passed",
  "provider": "node",
  "summary": {
    "total": 3,
    "passed": 3,
    "failed": 0
  },
  "cases": [
    {
      "name": "single",
      "status": "passed",
      "response": {
        "status": 200
      }
    }
  ]
}

Wasm size

Artifact	Default build	--experimental-native-size	Reduction
canonical-native.wasm	5.1 KiB (5,272 bytes)	4.5 KiB (4,570 bytes)	13.3%

The executable documentation gate rebuilds and measures both variants on 1.0.0-beta.9. These are uncompressed on-disk sizes, not transfer sizes or platform limits.

Handler

import { Pulse } from '@pulse-compute/pulse'

interface User {
  id: number
  name: string
}

interface Stats {
  score: number
}

interface Flags {
  enabled: boolean
}

const app = new Pulse({ auto: true })

// One structured origin.
app.get('/user', async (ctx) => {
  const user = await ctx
    .fetch('https://users.example.test/users/123')
    .json<User>()
  return ctx.json({ found: true, user })
})

// Multiple origins with explicit sequential awaits.
app.get('/user-summary', async (ctx) => {
  const user = await ctx
    .fetch('https://users.example.test/users/123')
    .json<User>()
  const stats = await ctx
    .fetch('https://stats.example.test/users/123')
    .json<Stats>()
  const flags = await ctx
    .fetch('https://flags.example.test/users/123')
    .json<Flags>()
  return ctx.json({
    id: user.id,
    name: user.name,
    score: stats.score,
    enabled: flags.enabled,
  })
})

// Multiple origins with explicit portable concurrency.
app.get('/user-summary-parallel', async (ctx) => {
  const { user, stats, flags } = await ctx.parallel({
    user: ctx.fetch('https://users.example.test/users/123').json<User>(),
    stats: ctx.fetch('https://stats.example.test/users/123').json<Stats>(),
    flags: ctx.fetch('https://flags.example.test/users/123').json<Flags>(),
  })
  return ctx.json({
    id: user.id,
    name: user.name,
    score: stats.score,
    enabled: flags.enabled,
  })
})

export default app

Project config

import { defineConfig } from '@pulse-compute/pulse'

export default defineConfig((_scope) => ({
  pulse: {
    entry: 'src/index.ts',
    tests: 'tests/pulse.harness.ts',
    defaultProfile: 'local',
    strict: true,
  },
  local: {
    host: 'node',
    target: 'native',
    outDir: 'dist',
    dev: {
      fetches: {
        'https://users.example.test/users/123': {
          value: { id: 123, name: 'Ada' },
          delayMs: 15,
        },
        'https://stats.example.test/users/123': {
          value: { score: 42 },
          delayMs: 5,
        },
        'https://flags.example.test/users/123': {
          value: { enabled: true },
          delayMs: 1,
        },
      },
    },
  },
}))

Test harness

const fetches = {
  'https://users.example.test/users/123': {
    value: { id: 123, name: 'Ada' },
    delayMs: 15,
  },
  'https://stats.example.test/users/123': {
    value: { score: 42 },
    delayMs: 5,
  },
  'https://flags.example.test/users/123': {
    value: { enabled: true },
    delayMs: 1,
  },
}

const summary = {
  id: 123,
  name: 'Ada',
  score: 42,
  enabled: true,
}

export default {
  cases: [
    {
      name: 'single',
      request: { path: '/user' },
      fetches,
      expect: {
        status: 200,
        json: { found: true, user: { id: 123, name: 'Ada' } },
      },
    },
    {
      name: 'sequential',
      request: { path: '/user-summary' },
      fetches,
      expect: { status: 200, json: summary },
    },
    {
      name: 'parallel',
      request: { path: '/user-summary-parallel' },
      fetches,
      expect: { status: 200, json: summary },
    },
  ],
}