fontinspect

Fontinspect is a command line tool that will trace the web font usage of a particular web page. It is a cut-down version of the engine that runs inside subfont, an automated font subsetter and loading optimizer.

This data-only version has been created to aid the W3C Web Font Working Group with the data analysis for the 2018 chartered Progressive Font Enrichment specification.

Installation

npm i -g fontinspect

Usage

fontinspect https://exampleurl.com

Output

The tool will output some status messages on STDERR and stream out the measured font usage on STDOUT.

Example output

$ bin/fontinspect https://www.zachleat.com/

[
  {
    "fontUrl": "https://www.zachleat.com/web/css/fonts/lato/2.0/LatoLatin-Italic-subset.woff2",
    "props": {
      "font-family": "LatoItalic",
      "font-weight": "normal",
      "font-style": "italic",
      "font-stretch": "normal",
      "src": "url(/web/css/fonts/lato/2.0/LatoLatin-Italic-subset.woff2) format(\"woff2\"),url(/web/css/fonts/lato/2.0/LatoLatin-Italic-subset.zopfli.woff) format(\"woff\")"
    },
    "characters": " (),.FILOSTUabcdefghilmnorstuvwxy",
    "codepoints": [
      32,
      40,
      41,
      44,
      46,
      70,
      73,
      76,
      79,
      83,
      84,
      85,
      97,
      98,
      99,
      100,
      101,
      102,
      103,
      104,
      105,
      108,
      109,
      110,
      111,
      114,
      115,
      116,
      117,
      118,
      119,
      120,
      121
    ],
    "textNodes": [
      " Flash of Invisible Text (FOIT)",
      " Flash of Unstyled Text (FOUT)",
      " First stage, Lato subset embedded",
      " Second stage, all web fonts finished."
    ]
  }
]

License

ISC