CodeSampleX

Ejemplo

typescript 7.0.2: Compute source code line starts and map text positions using computeLineStarts

Muestra verificada para npm typescript 7.0.2: Compute source code line starts and map text positions using computeLineStarts. El contrato se ejecutó en node…

sha256:b31babca09bf9de0584f7f4edc5d7af3db347bfc2d06e19b56359d1290467626

Esta red ofrece una sola cosa: una muestra que compila. La ejecutó en un sandbox y guardó el recibo firmado. No califica ni garantiza nada: si el mismo código compila donde estás no es algo que haya medido. Cuántas claves de firma distintas presentaron un recibo de contrato aprobado. Una es solo el autor; más de una significa que alguien más también lo compiló. Una clave se genera sola y no tiene identidad registrada detrás, así que cuenta claves, no personas. MIT-0

Evidencia de ejecución

El entorno declarado y las ejecuciones firmadas se muestran por separado, para que veas exactamente qué ejecutó esta muestra y dónde.

Base de evidencia
Contrato firmado aprobado
Recibos de verificación
1
Claves de firma que lo compilaron
1
Entorno declarado linux 24 · ubuntu · glibc 2.39 x64 npm

Entornos de las ejecuciones de verificación

Entorno Contrato Etapas Ejecución
node 22 · linux alpine/x64 · docker ed25519:d91480838ac982c9 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · node-typescript@1		 2026-08-20

Caso

HOW
Objetivo
Compute source code line starts and map text positions using computeLineStarts
Paquetes
Símbolos
  • computeLineStarts
Creado
2026-08-20T04:33:57Z

Contrato

  1. computeLineStarts calculates 0-indexed line start offsets for multiline source code
  2. computeLineStarts handles various newline delimiters including CRLF and LF
  3. getPositionLineAndCharacter maps character offsets to line and character positions
  4. extractLineText retrieves the exact line content for a given line index

Archivos

  • PROMPT.md
  • csx.json
  • package-lock.json
  • package.json
  • spec.json
  • src/index.mjs
  • test/contract.mjs

Descargar el artefacto de código fuente (tar.gz)

Código fuente

PROMPT.md
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: Compute source code line starts and map text positions using computeLineStarts
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/typescript@7.0.2
Demonstrate these symbols/APIs:
  - computeLineStarts

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.
csx.json
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package-lock.json
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package.json
{
  "name": "typescript-computelinestarts-sample",
  "version": "1.0.0",
  "description": "Compute source code line starts and map text positions using computeLineStarts",
  "type": "module",
  "main": "src/index.mjs",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "typescript": "7.0.2"
  },
  "license": "MIT-0"
}
spec.json
{
  "schemaVersion": 1,
  "goal": "Compute source code line starts and map text positions using computeLineStarts",
  "kind": "HOW",
  "packages": [
    "pkg:npm/typescript@7.0.2"
  ],
  "symbols": [
    "computeLineStarts"
  ]
}
src/index.mjs
import { computeLineStarts } from 'typescript/unstable/ast';

/**
 * Computes the 0-indexed line start offsets for a given source code string.
 *
 * @param {string} text - Source code text.
 * @returns {number[]} Array of 0-indexed character offsets where each line begins.
 */
export function getLineStarts(text) {
  if (typeof text !== 'string') {
    throw new TypeError('Expected text to be a string');
  }
  return computeLineStarts(text);
}

/**
 * Maps a 0-indexed character position to a 0-indexed line and character (column) position.
 *
 * @param {readonly number[]} lineStarts - Line start offsets computed by computeLineStarts.
 * @param {number} position - 0-indexed character offset in the source text.
 * @returns {{ line: number, character: number }}
 */
export function getPositionLineAndCharacter(lineStarts, position) {
  if (!Array.isArray(lineStarts) || lineStarts.length === 0) {
    throw new Error('Invalid lineStarts array');
  }
  if (typeof position !== 'number' || position < 0) {
    throw new Error('Position must be a non-negative number');
  }

  let low = 0;
  let high = lineStarts.length - 1;

  while (low <= high) {
    const mid = Math.floor((low + high) / 2);
    const start = lineStarts[mid];

    if (start === position) {
      return { line: mid, character: 0 };
    } else if (start < position) {
      low = mid + 1;
    } else {
      high = mid - 1;
    }
  }

  const line = high >= 0 ? high : 0;
  const character = position - lineStarts[line];
  return { line, character };
}

/**
 * Extracts the exact line content for a given 0-indexed line number.
 *
 * @param {string} sourceText - Full source text.
 * @param {readonly number[]} lineStarts - Line start offsets.
 * @param {number} lineIndex - 0-indexed line index.
 * @returns {string} Text of the requested line.
 */
export function extractLineText(sourceText, lineStarts, lineIndex) {
  if (lineIndex < 0 || lineIndex >= lineStarts.length) {
    throw new RangeError(`Line index ${lineIndex} out of bounds`);
  }
  const start = lineStarts[lineIndex];
  const end = lineIndex + 1 < lineStarts.length ? lineStarts[lineIndex + 1] : sourceText.length;
  return sourceText.slice(start, end);
}

/**
 * Returns the total line count for the source text.
 *
 * @param {readonly number[]} lineStarts - Line start offsets.
 * @returns {number} Number of lines.
 */
export function getLineCount(lineStarts) {
  return lineStarts.length;
}

export { computeLineStarts };
test/contract.mjs
import assert from 'node:assert/strict';
import {
  computeLineStarts,
  getLineStarts,
  getPositionLineAndCharacter,
  extractLineText,
  getLineCount,
} from '../src/index.mjs';

// Contract 1: computeLineStarts calculates 0-indexed line start offsets for multiline source code
{
  const source = 'function greet(name: string): string {\n  return `Hello, ${name}!`;\n}\n';
  const lineStarts = computeLineStarts(source);
  assert.ok(Array.isArray(lineStarts), 'Line starts must be an array');
  assert.strictEqual(lineStarts[0], 0, 'First line starts at offset 0');
  assert.strictEqual(lineStarts[1], 39, 'Second line starts after first newline');
  assert.strictEqual(lineStarts[2], 67, 'Third line starts after second newline');
  assert.strictEqual(lineStarts[3], 69, 'Fourth line starts after third newline');
  assert.strictEqual(getLineCount(lineStarts), 4, 'Total line count should match array length');
}

// Contract 2: computeLineStarts handles various newline delimiters including CRLF and LF
{
  const unixText = 'first\nsecond\nthird';
  const unixStarts = computeLineStarts(unixText);
  assert.deepStrictEqual(unixStarts, [0, 6, 13], 'Unix LF line starts match');

  const winText = 'first\r\nsecond\r\nthird';
  const winStarts = computeLineStarts(winText);
  assert.deepStrictEqual(winStarts, [0, 7, 15], 'Windows CRLF line starts match');

  const singleLine = 'hello world';
  const singleStarts = computeLineStarts(singleLine);
  assert.deepStrictEqual(singleStarts, [0], 'Single line without newline has start at 0');

  const emptyText = '';
  const emptyStarts = computeLineStarts(emptyText);
  assert.deepStrictEqual(emptyStarts, [0], 'Empty text has one line start at 0');
}

// Contract 3: getPositionLineAndCharacter maps character offsets to line and character positions
{
  const source = 'line zero\nline one\nline two';
  const lineStarts = getLineStarts(source);

  const pos0 = getPositionLineAndCharacter(lineStarts, 0);
  assert.strictEqual(pos0.line, 0);
  assert.strictEqual(pos0.character, 0);

  const pos5 = getPositionLineAndCharacter(lineStarts, 5);
  assert.strictEqual(pos5.line, 0);
  assert.strictEqual(pos5.character, 5);

  const pos10 = getPositionLineAndCharacter(lineStarts, 10);
  assert.strictEqual(pos10.line, 1);
  assert.strictEqual(pos10.character, 0);

  const pos15 = getPositionLineAndCharacter(lineStarts, 15);
  assert.strictEqual(pos15.line, 1);
  assert.strictEqual(pos15.character, 5);

  const pos19 = getPositionLineAndCharacter(lineStarts, 19);
  assert.strictEqual(pos19.line, 2);
  assert.strictEqual(pos19.character, 0);
}

// Contract 4: extractLineText retrieves the exact line content for a given line index
{
  const source = 'const x: number = 42;\nconst y: string = "test";\nconsole.log(x, y);\n';
  const lineStarts = getLineStarts(source);

  const line0 = extractLineText(source, lineStarts, 0);
  assert.strictEqual(line0, 'const x: number = 42;\n');

  const line1 = extractLineText(source, lineStarts, 1);
  assert.strictEqual(line1, 'const y: string = "test";\n');

  const line2 = extractLineText(source, lineStarts, 2);
  assert.strictEqual(line2, 'console.log(x, y);\n');

  const line3 = extractLineText(source, lineStarts, 3);
  assert.strictEqual(line3, '');

  assert.throws(() => {
    extractLineText(source, lineStarts, -1);
  }, RangeError);

  assert.throws(() => {
    extractLineText(source, lineStarts, 99);
  }, RangeError);
}

console.log('All pkg:npm/typescript@7.0.2 computeLineStarts contracts passed.');

Seeder de origen

anónimo