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(in promise) ReferenceError: x is not defined // 报错却不退出进程")]),s._v("\n"),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 123")]),s._v("\n")])]),s._v(" "),t("div",{staticClass:"line-numbers-wrapper"},[t("span",{staticClass:"line-number"},[s._v("1")]),t("br"),t("span",{staticClass:"line-number"},[s._v("2")]),t("br"),t("span",{staticClass:"line-number"},[s._v("3")]),t("br"),t("span",{staticClass:"line-number"},[s._v("4")]),t("br"),t("span",{staticClass:"line-number"},[s._v("5")]),t("br"),t("span",{staticClass:"line-number"},[s._v("6")]),t("br"),t("span",{staticClass:"line-number"},[s._v("7")]),t("br"),t("span",{staticClass:"line-number"},[s._v("8")]),t("br"),t("span",{staticClass:"line-number"},[s._v("9")]),t("br"),t("span",{staticClass:"line-number"},[s._v("10")]),t("br"),t("span",{staticClass:"line-number"},[s._v("11")]),t("br"),t("span",{staticClass:"line-number"},[s._v("12")]),t("br"),t("span",{staticClass:"line-number"},[s._v("13")]),t("br"),t("span",{staticClass:"line-number"},[s._v("14")]),t("br")])]),t("p",[s._v("上面代码中，"),t("code",[s._v("someAsyncThing")]),s._v("函数产生的 Promise 对象，内部有语法错误。浏览器运行到这一行，会打印出错误提示"),t("code",[s._v("ReferenceError: x is not defined")]),s._v("，但是不会退出进程、终止脚本执行，2 秒之后还是会输出"),t("code",[s._v("123")]),s._v("。这就是说，"),t("strong",[s._v("Promise 内部的错误不会影响到 Promise 外部的代码，通俗的说法就是“Promise 会吃掉错误”")]),s._v("。")]),s._v(" "),t("p",[s._v("这个脚本放在服务器执行，退出码就是"),t("code",[s._v("0")]),s._v("（即表示执行成功）。不过，Node 有一个"),t("code",[s._v("unhandledRejection")]),s._v("事件，专门监听未捕获的"),t("code",[s._v("reject")]),s._v("错误，上面的脚本会触发这个事件的监听函数，可以在监听函数里面抛出错误。")]),s._v(" "),t("div",{staticClass:"language-javascript line-numbers-mode"},[t("pre",{pre:!0,attrs:{class:"language-javascript"}},[t("code",[s._v("process"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("on")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token string"}},[s._v("'unhandledRejection'")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" 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