{
    "compact": false,
    "presets": [
        ["env",
        {
            "targets":
            {
                "browsers": ["last 2 versions", "safari >= 7", "ie >= 9"]
            }
        }],
        "stage-2" //ES7第三阶段语法提案的转码规
    ],
    "plugins": [
        "transform-runtime",
        "transform-object-assign", //Object.assign转换
        ["transform-es2015-classes",
        { //转换es6 class插件
            "loose": false
        }],
        ["transform-es2015-modules-commonjs",
        { //转换es6 module插件
            "loose": false
        }]
    ]
}