medium/flow-to-ts/extract-ts-errors

extract-ts-errors.js

/**
 * Usage: tsc | node ./extract-ts-errors.js
 *
 * This script prints the list of encountered TS errors, ordered by ascending occurences.
 * Also, it logs the output of `tsc` into `./tsc.log`, for easier searching.
 */

const readline = require('readline');
const fs = require('fs');
const path = require('path');

const Table = require('cli-table');
const chalk = require('chalk');

const OUTPUT_TXT_FILE = path.join(__dirname, 'tsc.log');

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  terminal: false,
});

const GENERIC_ERROR_REGEX = /^(.+)\(.+\): error TS([0-9]+): (.+)$/;

const errorsPerCode = new Map();
const errorsPerFile = new Map();
let errorsCount = 0;

const lines = [];
rl.on('line', line => {
  lines.push(line);
  const match = line.match(GENERIC_ERROR_REGEX);

  if (!match) {
    return;
  }

  const [, filePath, code, _message] = match;

  const codeErrorCount = errorsPerCode.get(code) ?? 0;
  const fileErrorCount = errorsPerFile.get(filePath) ?? 0;

  errorsPerCode.set(code, codeErrorCount + 1);
  errorsPerFile.set(filePath, fileErrorCount + 1);
  errorsCount += 1;
});

rl.on('close', () => {
  console.log(chalk.bold.italic('\n# Errors per code (desc by error count)\n'));

  console.log(`Numbers of different TS errors: ${errorsPerCode.size}\n`);

  const codeTable = new Table({
    head: ['Code', '# of errors'],
    colWidths: [10, 20],
  });

  [...errorsPerCode]
    .sort((a, b) => b[1] - a[1])
    .forEach(([code, count]) => {
      codeTable.push([`TS${code}`, count]);
    });

  console.log(codeTable.toString());

  console.log(chalk.bold.italic('\n# Errors per file (desc by error count)\n'));

  console.log(`Numbers of files: ${errorsPerFile.size}\n`);

  const fileTable = new Table({
    head: ['File', '# of errors'],
    colWidths: [90, 20],
  });

  [...errorsPerFile]
    .sort((a, b) => b[1] - a[1])
    .forEach(([path, count]) => {
      fileTable.push([path, count]);
    });

  console.log(fileTable.toString());

  console.log(`\n${chalk.bold.yellow.underline(`Remaining errors: ${errorsCount}`)}`);

  fs.writeFileSync(OUTPUT_TXT_FILE, lines.join('\n'));
});