babel-test262 Tests are transpiled using babel-preset-env. Usage Run all tests run_tests Run an entier test suite run_tests built-ins Run a test suite with a folder run_tests language asi Run a single test run_tests language asi S7.9.2_A1_T1 It will then expend to test262/test/language/asi/S7.9.2_A1_T1.js Configuration Browser target Export TARGET_BROWSERS.