How to include a Typescript type check step into a `build.sh` script file?

Question

I'd like to incorporate a type check in my build process.

I keep my build process in a build.sh file where a call multiple CLI like:

// TYPE CHECK HERE <---
rimraf dist
webpack...
babel...

I'd like to type check my /src folder and stop my build process if it find any type errors.

How can I do that? Should I use tsc? Is there any option I need to add to make it stop in case it finds any errors?

I'm trying implement this basic functionality example:

test.sh

tsc src/testScript.ts --noEmit --skipLibCheck
echo "AFTER TSC"

I've intentionally added this error to the testScript.ts.

You can see that the rest of the test.sh script just keeps running. Is there a way to check if the tsc call has found any errors? Then I could check the result and stop the script at that point.

Answer 1

Here is how I've implemented this:

build.sh

TYPE_ERRORS="$(tsc --project ./tsconfig.json)"

if [[ -n $TYPE_ERRORS ]]; then
  echo "FOUND ERRORS"
  echo $TYPE_ERRORS
  echo "WILL EXIT NOW"
  exit
fi

echo "NO ERRORS WERE FOUND"

The result of the tsc will be stored in $TYPE_ERRORS. If the result is not empty, it will log the errors and exit the script. Else, the script will continue and log NO ERRORS WERE FOUND.

Note: Instead of logging the errors by doing echo $TYPE_ERRORS, you can also call the tsc command again, because the log will be prettier (with colors). Like:

build.sh

TYPE_ERRORS="$(tsc --project ./tsconfig.json)"

if [[ -n $TYPE_ERRORS ]]; then
  echo "FOUND ERRORS"
  tsc --project ./tsconfig.json   # THIS WILL LOG PRETTIER LOGS
  echo "WILL EXIT NOW"
  exit
fi

echo "NO ERRORS WERE FOUND"

The log from echo $TYPE_ERRORS will be plain text only (no colors).

---

The code above will look in tsconfig.json to see which compiler options should be applied and also which folders must by compiled.

But you can also specify folder/file, like:

tsc src/someFile.ts --noEmit --someOtherOption

---

This is how I call the .sh file from an npm script:

package.json

{
  "scripts": {
    "build: "./my-bash-scripts-folder/build.sh"
  }
}

Than I run it as npm run build like always.

---

UPDATE: USING EXIT CODES

You can use the exit code from the tsc script to know if it has thrown any errors.

The standard is 0 for successful runs.

tsc --project ./tsconfig.json
TYPE_CHECK_EXIT_CODE=$?

if [[ $TYPE_CHECK_EXIT_CODE == "0" ]]; then
  echo "TYPE CHECK - SUCCESS"
else
  echo "TYPE CHECK - FAILED"
fi