List of strict null-checked files inside a TypeScript project

tsc_strict_null_checks_ok.ts

#!/bin/bash

# Returns a list of strict null-checked files inside the current directory.
# Useful for gradually introducing the `--strictNullCheck` flag to a
# TypeScript project.
#
# See: https://code.visualstudio.com/blogs/2019/05/23/strict-null

TS_FLAGS='--strictNullChecks --outDir=/dev/null'

filter_defs() {
  grep -v node_modules \
  | grep -v '.d.ts$' \
  | sort \
  | uniq
}

TS_FILES=$(find . -name '*.ts' \
  | cut -d/ -f2- \
  | filter_defs)
TS_ERRORS=$(yarn tsc --noEmit $TS_FLAGS 2> /dev/null \
  | grep -o '.*\.ts[x]*([0-9,]*): error' \
  | cut -d\( -f1 \
  | filter_defs)

comm -23 <(echo "$TS_FILES") <(echo "$TS_ERRORS")