guess.js

"use strict";

const path = require("path");
const ts = require("typescript");

const cwd = process.cwd();
const compilerOptions = loadCompilerOptions(cwd) || {};
const extensions = ["ts", "tsx"];
if (compilerOptions.allowJs) {
  extensions.push("js");
  extensions.push("jsx");
}

let testDir = "test";
const packageData = require(path.join(cwd, "package.json"));
if (
  packageData &&
  typeof packageData.directories === "object" &&
  typeof packageData.directories.test === "string"
) {
  testDir = packageData.directories.test;
}
const pattern = path.join(testDir, `**/*.@(${extensions.join("|")})`);

require("./index")({ cwd, pattern, extensions });

function loadCompilerOptions(cwd) {
  const tsconfigPath = ts.findConfigFile(cwd, ts.sys.fileExists);
  if (!tsconfigPath) {
    return null;
  }
  const result = ts.readConfigFile(tsconfigPath, ts.sys.readFile);
  if (result.error) {
    throw new Error(result.error.messageText);
  }
  if (result.config && result.config.compilerOptions) {
    const basepath = path.dirname(tsconfigPath);
    const { options } = ts.parseJsonConfigFileContent(result.config, ts.sys, basepath);
    return options;
  }
  return null;
}