jest-runner-tsd/src/formatter.js

Run your TypeScript type tests using Jest

const { posix, relative, sep } = require('path');
const { codeFrameColumns } = require('@babel/code-frame');
const ts = require('@tsd/typescript');
const chalk = require('chalk');
/** @typedef {import('tsd-lite').TsdResult} TsdResult */

const NOT_EMPTY_LINE_REGEXP = /^(?!$)/gm;
const INDENT = '  ';

/**
 * @param {string} lines
 * @param {number} level
 */
const indentEachLine = (lines, level) =>
  lines.replace(NOT_EMPTY_LINE_REGEXP, INDENT.repeat(level));

const BULLET = '\u25cf ';

/**
 * @param {string} title
 */
const makeTitle = title => indentEachLine(BULLET + title + '\n', 1);

/**
 * @param {string} input
 */
const normalizeSlashes = input => input.split(sep).join(posix.sep);

/**
 * @param {ts.SourceFile} file
 * @param {number | undefined} start
 */
function getCodeFrameAndLocation(file, start) {
  if (start === undefined) return;

  const { line, character } = file.getLineAndCharacterOfPosition(start);

  const codeFrame = codeFrameColumns(
    file.text,
    { start: { line: line + 1, column: character + 1 } },
    { highlightCode: true, linesAbove: 0, linesBelow: 0 }
  );

  const location =
    chalk.dim('at ') +
    chalk.cyan(normalizeSlashes(relative('', file.fileName))) +
    chalk.dim(':' + (line + 1) + ':' + (character + 1));

  return [codeFrame, indentEachLine(location, 1)].join('\n\n');
}

/**
 * @param {Array<TsdResult>} tsdResults
 */
module.exports.formatTsdResults = tsdResults => {
  const title = chalk.bold.red(makeTitle('tsd typecheck'));

  const messages = tsdResults.map(result => {
    const message = ts.flattenDiagnosticMessageText(result.messageText, '\n');

    const codeFrameAndLocation = result.file
      ? getCodeFrameAndLocation(result.file, result.start)
      : undefined;

    if (codeFrameAndLocation !== undefined) {
      return [
        indentEachLine(message, 2),
        indentEachLine(codeFrameAndLocation, 2),
      ].join('\n\n');
    }

    return [indentEachLine(message, 2)].join('\n\n');
  });

  return [title, messages.join('\n\n'), ''].join('\n');
};