Check TypeScript files for type errors (ignoring imported files)

check.ts

const _ = require('lodash')
const ts = require('typescript')
const config = require('./tsconfig.json')

let exitStatus = 0
const files = process.argv.slice(2)
const compilerOptions = _.omit(config.compilerOptions, ['moduleResolution'])
compilerOptions.noEmit = true
compilerOptions.lib = ['lib.dom.d.ts']

function compile(fileNames, options) {
  let program = ts.createProgram(fileNames, options)
  let allDiagnostics = ts.getPreEmitDiagnostics(program)

  allDiagnostics.forEach((diagnostic) => {
    if (diagnostic.file) {
      if (fileNames.indexOf(diagnostic.file.fileName) < 0) {
        return
      }

      let { line, character } = diagnostic.file.getLineAndCharacterOfPosition(
        diagnostic.start
      )
      let message = ts.flattenDiagnosticMessageText(
        diagnostic.messageText,
        '\n'
      )
      console.log(
        `${diagnostic.file.fileName} (${line + 1},${character +
          1}): ${message} \n`
      )
      exitStatus = 1
    } else {
      console.log(
        `${ts.flattenDiagnosticMessageText(diagnostic.messageText, '\n')}`
      )
    }
  })
}

console.log(
  `Checking type errors in the following files using TS ${ts.version}:`,
  files,
  '\n'
)
files && compile(files, compilerOptions)
process.exit(exitStatus)