typescriptFormatter.js

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

'use strict';

const os = require('os');
const codeFrame = require('@babel/code-frame').codeFrameColumns;
const chalk = require('chalk');
const fs = require('fs');

const types = { diagnostic: 'TypeScript', lint: 'TSLint' };

function formatter(message, useColors) {
  const { type, severity, file, line, content, code, character } =
    typeof message.getFile === 'function'
      ? {
          type: message.getType(),
          severity: message.getSeverity(),
          file: message.getFile(),
          line: message.getLine(),
          content: message.getContent(),
          code: message.getCode(),
          character: message.getCharacter(),
        }
      : message;

  const colors = new chalk.constructor({ enabled: useColors });
  const messageColor = message.isWarningSeverity() ? colors.yellow : colors.red;
  const fileAndNumberColor = colors.bold.cyan;

  const source = file && fs.existsSync(file) && fs.readFileSync(file, 'utf-8');
  const frame = source
    ? codeFrame(
        source,
        { start: { line: line, column: character } },
        { highlightCode: useColors }
      )
        .split('\n')
        .map(str => '  ' + str)
        .join(os.EOL)
    : '';

  return [
    messageColor.bold(`${types[type]} ${severity.toLowerCase()} in `) +
      fileAndNumberColor(`${file}(${line},${character})`) +
      messageColor(':'),
    content +
      '  ' +
      messageColor.underline((type === 'lint' ? 'Rule: ' : 'TS') + code),
    '',
    frame,
  ].join(os.EOL);
}

module.exports = formatter;