Promise 異步處理方案 (Snippets)

創建Promise

"創建Promise": {
    "prefix": "$Promise0001",
    "body": [
        "//創建Promise",
        "//1.一旦新建它就會 \"立即執行\"",
        "const ${1:promise名} = new Promise((resolve, reject) => {",
        "    try {",
        "        //做一些事",
        "        resolve(${2:成功時回傳值});",
        "    } catch (Error) {",
        "        reject(Error);",
        "    }",
        "})",
        "    .then(Result => {",
        "        ResultJson = Result.clone().json();//Response.clone()",
        "        //做一些事情",
        "        console.log(ResultJson)",
        "        return ResultJson;",
        "    })",
        "    .then((PreResult) => {",
        "        //前一個then()內的 return ResultJson 將成為 PreResult",
        "        //做一些事情",
        "    })",
        "    .catch((Error) => {",
        "        //catch函數是.then(null, rejection)或.then(undefined, rejection)的別名，用於捕獲處理錯誤。",
        "        //如果前面的異步操作拋出錯誤，狀態就會變為rejected，就會調用catch函數內指定的回調函數，處理這個錯誤。",
        "        //Promise物件的錯誤，會一直向後傳遞，直到被捕獲為止。",
        "        console.log(Error)",
        "    })",
        "    .finally(() => {",
        "        //finally()用於指定不管Promise物件最後狀態如何，都會執行的操作。",
        "        //而finally()的回調函數不接受任何參數，這代表著沒有辦法知道，前面的Promise狀態到底是resolved還是rejected。",
        "        //即是說，finally()裡面的操作，應該是與狀態無關的，不依賴於Promise的執行結果。",
        "    });"
    ],
    "description": "創建Promise"
}