{ "presets": [ ["env", { "modules": false, "targets": { // See config/browser.rb "browsers": [ "> 1%", "Chrome >= 40", "IE >= 11", "Edge >= 12", "Firefox >= 45", "Opera >= 19", "Safari >= 8", "iOS >= 8" ], "uglify": true }, "useBuiltIns": true }] ], "plugins": [ "syntax-dynamic-import", "transform-object-rest-spread", ["transform-class-properties", { "spec": true }] ] }