Font fallback differentials

fonts.fallback-differentials

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JSON

Selected signal results for external comparison. Field statuses, controls and exact values are retained.

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Source

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// Test source pending.

Definition

Measures candidate font requests against generic fallback baselines.

Find it in the repository

Collector source: core/signals/fonts/fallback-differentials.ts
Export: measurementModule · Signal object
Field definitions: core/definitions/fonts/fallback-differentials.ts
Capture membership: Product capture · common/capture/product.ts
Page registration: app/signals/registry.ts
Field projection: core/results/measurement.ts

Execution contract

Signal: fonts.fallback-differentials
Collector: fonts.fallback-differentials
API / surface: core/signals/fonts/fallback-differentials.ts
Timeout: 1250 ms
Companion signals: None
Fixture inputs: Inline owned corpora (listed below)

core/fixtures/fonts/fallback-differentials.ts · sha256:cc629f05f3a9a7b117784f22d7e7614ee115f2e986bec6b4277647326a7386a3

Exact request inputs

[
  {
    "key": "fonts.fallback-differentials.responses",
    "inputs": {
      "Calibri": {
        "name": "Calibri",
        "text": "mmmmmmmmmmlli Wi01国é",
        "fallback": [
          "serif",
          "sans-serif",
          "monospace"
        ],
        "interpretation": "fallback response, not installed-font inventory"
      },
      "Segoe UI": {
        "name": "Segoe UI",
        "text": "mmmmmmmmmmlli Wi01国é",
        "fallback": [
          "serif",
          "sans-serif",
          "monospace"
        ],
        "interpretation": "fallback response, not installed-font inventory"
      },
      "Helvetica Neue": {
        "name": "Helvetica Neue",
        "text": "mmmmmmmmmmlli Wi01国é",
        "fallback": [
          "serif",
          "sans-serif",
          "monospace"
        ],
        "interpretation": "fallback response, not installed-font inventory"
      },
      "Menlo": {
        "name": "Menlo",
        "text": "mmmmmmmmmmlli Wi01国é",
        "fallback": [
          "serif",
          "sans-serif",
          "monospace"
        ],
        "interpretation": "fallback response, not installed-font inventory"
      },
      "-apple-system-body": {
        "name": "-apple-system-body",
        "text": "mmmmmmmmmmlli Wi01国é",
        "fallback": [
          "serif",
          "sans-serif",
          "monospace"
        ],
        "interpretation": "fallback response, not installed-font inventory"
      },
      "-apple-system-headline": {
        "name": "-apple-system-headline",
        "text": "mmmmmmmmmmlli Wi01国é",
        "fallback": [
          "serif",
          "sans-serif",
          "monospace"
        ],
        "interpretation": "fallback response, not installed-font inventory"
      }
    },
    "controls": {}
  }
]

One collector runs per invocation. Results and JSON select this signal’s fields; any companions execute in the same collector.

Generated source manifest lists runtime files, fixture URLs and content digests for this build. The Source tab provides a copyable console sample.

Run and edit locally

From the repository root, start the Astro app, then open /signals/fonts.fallback-differentials. Edit the collector source and reload the page to load its new build.

pnpm run dev:web

In a browser module served by this repository’s Vite graph:

import { createCollector } from "/core/collect"
import { measurementModule } from "/core/signals/fonts/fallback-differentials"

const signal = measurementModule
const collector = createCollector()
const suite = { signals: [signal] }
const result = await collector.collect(suite)

Reuse the collector owner for repeated calls so collection can enforce cleanup. This returns the collector’s raw result; app/signals/projection.ts selects the retained fields shown on this page.

rg -n 'measurementModule' core app tests
pnpm run check
pnpm run test tests/unit/app/focused-projection.test.ts