wren/glyph Public Public: anyone can read this; nobody can change it.

/**

 * The look holds: the tokens compile to both themes, every pair of colours

 * a person must read meets WCAG AA in both, and no colour is spelled out

 * anywhere but design/tokens.json.

 */

import { expect, test } from "bun:test";

import { mkdirSync, mkdtempSync, writeFileSync } from "node:fs";

import { tmpdir } from "node:os";

import { join } from "node:path";

import { lint, rawColours, unknownTokens } from "../scripts/lint-design.ts";

import { compile, flatten, token, tokens, tokensCss } from "./tokens.ts";

test("the tokens compile: light on :root, dark for the system and for data-theme", () => {

  expect(tokensCss).toContain(`--color-bg: ${token("color-bg")};`);

  expect(tokensCss).toContain("--space-4: 1rem;");

  expect(tokensCss).toContain(

    '--font-sans: system-ui, -apple-system, "Segoe UI", sans-serif;',

  );

  expect(tokensCss).toContain("@media (prefers-color-scheme: dark)");

  expect(tokensCss).toContain(':root:not([data-theme="light"])');

  expect(tokensCss).toContain(':root[data-theme="dark"]');

  // Every colour has a dark value, or the dark theme would inherit a light one.

  for (const t of tokens.filter((t) => t.type === "color"))

    expect([t.name, t.dark !== undefined]).toEqual([t.name, true]);

  expect(

    tokensCss.split(`--color-bg: ${token("color-bg", "dark")};`).length,

  ).toBe(3);

});

test("tokens that do not read stop the app, with the path named", () => {

  expect(() => flatten({ color: { bg: { $value: "#fff" } } })).toThrow(

    "color.bg: no $type",

  );

  expect(() =>

    flatten({

      color: { $type: "color", bg: { $value: "red; } body { display: none" } },

    }),

  ).toThrow("color.bg: $value is not a CSS value");

  expect(() =>

    flatten({ color: { $type: "color", "b g": { $value: "#fff" } } }),

  ).toThrow("not a name CSS can carry");

  expect(

    compile(flatten({ size: { $type: "dimension", tap: { $value: "44px" } } })),

  ).toContain("--size-tap: 44px;");

});

// WCAG 2 relative luminance and contrast, from a #rrggbb.

const luminance = (hex: string): number => {

  const [r, g, b] = [1, 3, 5].map((i) => {

    const c = parseInt(hex.slice(i, i + 2), 16) / 255;

    return c <= 0.03928 ? c / 12.92 : ((c + 0.055) / 1.055) ** 2.4;

  }) as [number, number, number];

  return 0.2126 * r + 0.7152 * g + 0.0722 * b;

};

const contrast = (a: string, b: string): number => {

  const [x, y] = [luminance(a), luminance(b)].sort((p, q) => q - p) as [

    number,

    number,

  ];

  return (x + 0.05) / (y + 0.05);

};

test("every pair a person reads is at least 4.5:1, in both themes", () => {

  const pairs = [

    ["color-fg", "color-bg"],

    ["color-fg", "color-surface"],

    ["color-muted", "color-bg"],

    ["color-muted", "color-surface"],

    ["color-accent", "color-bg"],

    ["color-accent", "color-surface"],

    ["color-accent-fg", "color-accent"],

    ["color-toast-fg", "color-toast-bg"],

  ] as const;

  for (const mode of ["light", "dark"] as const)

    for (const [fg, bg] of pairs) {

      const ratio = contrast(token(fg, mode), token(bg, mode));

      expect([mode, fg, bg, ratio >= 4.5]).toEqual([mode, fg, bg, true]);

    }

});

test("the app spells out no colour but in its tokens", () => {

  expect(lint(join(import.meta.dir, ".."))).toEqual([]);

});

test("the lint refuses a raw colour and a token that is not there", () => {

  expect(

    rawColours(

      "a.css",

      ".x { color: #ff0000; }\n.y { background: rgb(0 0 0); }",

    ),

  ).toEqual([

    "a.css:1: raw colour #ff0000 — name it in design/tokens.json and use var(--…)",

    "a.css:2: raw colour rgb( — name it in design/tokens.json and use var(--…)",

  ]);

  // Not colours: an entity, an id selector's word, a pull number.

  expect(rawColours("a.ts", "`'` #notes pull #12 #abcdefg")).toEqual([]);

  expect(

    unknownTokens(

      "a.css",

      ".x { color: var(--color-fg); gap: var(--spcae-2); }",

    ),

  ).toEqual(["a.css:1: --spcae-2 is not a token in design/tokens.json"]);

  const root = mkdtempSync(join(tmpdir(), "app-lint-"));

  mkdirSync(join(root, "static"));

  mkdirSync(join(root, "src"));

  writeFileSync(join(root, "static", "extra.css"), "a {\n  color: #fff;\n}\n");

  writeFileSync(join(root, "src", "ok.test.ts"), "const red = '#f00';\n");

  expect(lint(root)).toEqual([

    "static/extra.css:2: raw colour #fff — name it in design/tokens.json and use var(--…)",

  ]);

});