@xterm/addon-fit 0.10.0: FitAddon.proposeDimensions

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify FitAddon.proposeDimensions in pkg:npm/%40xterm/addon-fit@0.10.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/%40xterm/addon-fit@0.10.0
Demonstrate these symbols/APIs:
  - FitAddon.proposeDimensions

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:42e9b0eddfd2ca8fe0f11bddbde43555487ec19f0f7e2e1ca3de3d062128e481","contract":["FitAddon.prototype.proposeDimensions is a function","proposeDimensions returns undefined when addon is not activated with a terminal","proposeDimensions returns undefined when terminal element or parentElement is missing","proposeDimensions returns undefined when renderService cell dimensions are zero","proposeDimensions calculates cols and rows from parent element dimensions and cell size","proposeDimensions accounts for terminal element padding and scrollbar width when scrollback is enabled","proposeDimensions ignores scrollbar width when scrollback is zero","proposeDimensions enforces minimum bounds of 2 columns and 1 row"],"goal":"verify FitAddon.proposeDimensions in pkg:npm/%40xterm/addon-fit@0.10.0","kind":"HOW","packages":["pkg:npm/%40xterm/addon-fit@0.10.0"],"schemaVersion":1,"symbols":["FitAddon.proposeDimensions"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"npm","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/%40xterm/addon-fit@0.10.0"],"schemaVersion":1,"subject":"pkg:npm/%40xterm/addon-fit@0.10.0","symbols":["FitAddon.proposeDimensions"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-addon-fit-propose-dimensions",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-addon-fit-propose-dimensions",
      "version": "1.0.0",
      "dependencies": {
        "@xterm/addon-fit": "0.10.0"
      }
    },
    "node_modules/@xterm/addon-fit": {
      "version": "0.10.0",
      "resolved": "https://registry.npmjs.org/@xterm/addon-fit/-/addon-fit-0.10.0.tgz",
      "integrity": "sha512-UFYkDm4HUahf2lnEyHvio51TNGiLK66mqP2JoATy7hRZeXaGMRDr00JiSF7m63vR5WKATF605yEggJKsw0JpMQ==",
      "license": "MIT",
      "peerDependencies": {
        "@xterm/xterm": "^5.0.0"
      }
    },
    "node_modules/@xterm/xterm": {
      "version": "5.5.0",
      "resolved": "https://registry.npmjs.org/@xterm/xterm/-/xterm-5.5.0.tgz",
      "integrity": "sha512-hqJHYaQb5OptNunnyAnkHyM8aCjZ1MEIDTQu1iIbbTD/xops91NB5yq1ZK/dC2JDbVWtF23zUtl9JE2NqwT87A==",
      "license": "MIT",
      "peer": true
    }
  }
}

{
  "name": "sample-addon-fit-propose-dimensions",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "dependencies": {
    "@xterm/addon-fit": "0.10.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify FitAddon.proposeDimensions in pkg:npm/%40xterm/addon-fit@0.10.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/%40xterm/addon-fit@0.10.0"
  ],
  "symbols": [
    "FitAddon.proposeDimensions"
  ]
}

import assert from 'node:assert/strict';

// Node.js compatibility: @xterm/addon-fit expects global `self` and `window`
globalThis.self = globalThis;

// Dynamic import ensures globalThis.self is defined before evaluating addon-fit module
const { FitAddon } = await import('@xterm/addon-fit');

// 1. FitAddon.prototype.proposeDimensions is a function
const fitAddon = new FitAddon();
assert.equal(typeof fitAddon.proposeDimensions, 'function');

// 2. proposeDimensions returns undefined when addon is not activated with a terminal
assert.equal(fitAddon.proposeDimensions(), undefined);

// 3. proposeDimensions returns undefined when terminal element or parentElement is missing
const unattachedTerminal = {
  element: null,
  options: { scrollback: 1000 },
  _core: {}
};
fitAddon.activate(unattachedTerminal);
assert.equal(fitAddon.proposeDimensions(), undefined);

const terminalWithoutParent = {
  element: {},
  options: { scrollback: 1000 },
  _core: {}
};
fitAddon.activate(terminalWithoutParent);
assert.equal(fitAddon.proposeDimensions(), undefined);

// 4. proposeDimensions returns undefined when renderService cell dimensions are zero
const parentElement = {};
const terminalElement = { parentElement };
const terminalWithZeroCell = {
  element: terminalElement,
  options: { scrollback: 1000 },
  _core: {
    _renderService: {
      dimensions: {
        css: {
          cell: { width: 0, height: 17 }
        }
      }
    },
    viewport: { scrollBarWidth: 15 }
  }
};
globalThis.window = {
  getComputedStyle: () => ({
    getPropertyValue: () => '100px'
  })
};
fitAddon.activate(terminalWithZeroCell);
assert.equal(fitAddon.proposeDimensions(), undefined);

// 5. proposeDimensions calculates cols and rows from parent element dimensions and cell size
const mockTerminal = {
  element: terminalElement,
  options: { scrollback: 1000 },
  _core: {
    _renderService: {
      dimensions: {
        css: {
          cell: { width: 10, height: 20 }
        }
      }
    },
    viewport: { scrollBarWidth: 15 }
  }
};

globalThis.window = {
  getComputedStyle: (el) => {
    if (el === parentElement) {
      return {
        getPropertyValue: (prop) => {
          if (prop === 'width') return '815px'; // 815 - 0 padding - 15 scrollbar = 800 -> 800 / 10 = 80 cols
          if (prop === 'height') return '500px'; // 500 - 0 padding = 500 -> 500 / 20 = 25 rows
          return '0px';
        }
      };
    }
    if (el === terminalElement) {
      return {
        getPropertyValue: () => '0px'
      };
    }
    return { getPropertyValue: () => '0px' };
  }
};

fitAddon.activate(mockTerminal);
const dims1 = fitAddon.proposeDimensions();
assert.deepEqual(dims1, { cols: 80, rows: 25 });

// 6. proposeDimensions accounts for terminal element padding and scrollbar width when scrollback is enabled
globalThis.window = {
  getComputedStyle: (el) => {
    if (el === parentElement) {
      return {
        getPropertyValue: (prop) => {
          if (prop === 'width') return '1000px';
          if (prop === 'height') return '600px';
          return '0px';
        }
      };
    }
    if (el === terminalElement) {
      return {
        getPropertyValue: (prop) => {
          if (prop === 'padding-left') return '10px';
          if (prop === 'padding-right') return '15px';
          if (prop === 'padding-top') return '20px';
          if (prop === 'padding-bottom') return '20px';
          return '0px';
        }
      };
    }
    return { getPropertyValue: () => '0px' };
  }
};

// availableWidth = 1000 - (10 + 15) - 15 = 960 -> 960 / 10 = 96 cols
// availableHeight = 600 - (20 + 20) = 560 -> 560 / 20 = 28 rows
const dims2 = fitAddon.proposeDimensions();
assert.deepEqual(dims2, { cols: 96, rows: 28 });

// 7. proposeDimensions ignores scrollbar width when scrollback is zero
mockTerminal.options.scrollback = 0;
// availableWidth = 1000 - (10 + 15) - 0 = 975 -> 975 / 10 = 97 cols (Math.floor(97.5))
// availableHeight = 600 - 40 = 560 -> 560 / 20 = 28 rows
const dims3 = fitAddon.proposeDimensions();
assert.deepEqual(dims3, { cols: 97, rows: 28 });

// 8. proposeDimensions enforces minimum bounds of 2 columns and 1 row
globalThis.window = {
  getComputedStyle: () => ({
    getPropertyValue: () => '0px'
  })
};
const dimsMin = fitAddon.proposeDimensions();
assert.deepEqual(dimsMin, { cols: 2, rows: 1 });

console.log('All FitAddon.proposeDimensions contract tests passed.');