告别if else

逻辑运算

||

let a = obj || "-";

等同于

let a;
if (a === 0 || a === null || a === undefined || a === "" || a === false) {
  a = "-";
} else {
  a = obj;
}

??

let a = obj ?? "-";

等同于

let a;
if (a === null || a === undefined) {
  a = "-";
} else {
  a = obj;
}

!!

let a = "";
if (!!obj) {
  a = obj.name;
}

等同于

let a = "";
if (obj !== null && obj !== undefined && obj != "") {
  a = obj.name;
}

三目运算

let a = isTrump ? "disappointing" : "Excited!";

等同于

let a;
if (isTrump) {
  a = "disappointing";
} else {
  a = "Excited!";
}

简化多重、嵌套判断

Array.includes

const result = ["a", "b", "c", "d", "e"];
if (result.includes("a")) console.log("!");

等同于

if (param === "a" || param === "b" || param === "c") {
  console.log("!");
}