JS 代碼質量優化

if (x === "a" || x === "b" || x === "c") {
}

// 優化後
if (["a", "b", "c"].includes(x)) {
}

//對於我們有 if..else 條件，並且裡面不包含大量的邏輯時，是一個比較大的捷徑。
let a = null;
if (x > 1) {
  a = true;
} else {
  a = false;
}

// 優化後
const a = x > 1 ? true : false;
//或
const a = x > 1;

const config = { a: 1, b: 2 };
const a = config.a;
const b = config.b;

// 優化後
const { a, b } = config;

const fc = (name) => {
  const breweryName = name || "默認值";
};

// 優化後
const fc = (name = "默認值") => {
  const breweryName = name;
};

function fc(currPage, totalPage) {
  if (currPage <= 0) {
    currPage = 0;
    jump(currPage); // 跳轉
  } else if (currPage >= totalPage) {
    currPage = totalPage;
    jump(currPage); // 跳轉
  } else {
    jump(currPage); // 跳轉
  }
}

// 優化後
const fc = (currPage, totalPage) => {
  if (currPage <= 0) {
    currPage = 0;
  } else if (currPage >= totalPage) {
    currPage = totalPage;
  }
  jump(currPage); // 把跳轉函數獨立出來
};

let a;
if (b !== null || b !== undefined || b !== "") {
  a = b;
} else {
  a = "other";
}

// 優化後
const a = b || "other";

let a;
if (b !== null || b !== undefined) {
  a = b;
} else {
  a = "other";
}

// 優化後
const a = b ?? "other";

if (test1) {
  callMethod(); // 調用方法
}

// 優化後
test1 && callMethod();

function checkReturn() {
  if (!(test === undefined)) {
    return test;
  } else {
    return callMe("test");
  }
}

// 優化後
const checkReturn = () => test || callMe("test");

let test = 1;
if (test == 1) {
  fc1();
} else {
  fc1();
}

// 優化後
(test === 1 ? fc1 : fc2)();

switch (index) {
  case 1:
    fc1();
    break;
  case 2:
    fc2();
    break;
  case 3:
    fc3();
    break;
  // And so on...
}

// 優化後
const fcs = {
  1: fc1,
  2: fc2,
  3: fc3,
};
fcs[index]();

const data = [
  {
    name: "abc",
    type: "test1",
  },
  {
    name: "cde",
    type: "test2",
  },
];

let findData;
for (const item of data) {
  if (item.type === "test1") {
    findData = item;
  }
}

// 優化後
const findData = data.find((item) => item.type === "test1");

let test = "";
for (let i = 0; i < 5; i++) {
  test += "test ";
}

// 優化後
"test ".repeat(5);

// 優化後
const a = [76, 3, 663, 6, 4, 4, 5, 234, 5, 24, 5, 7, 8];
console.log(Math.max(...a));
console.log(Math.min(...a));