一些在前端项目中会用到的快捷操作，下面的代码都可以直接复制到控制台运行。
数字取整
let floatNum = 100.5;
let intNum = ~~floatNum;
console.log(intNum); // 100
字符串转数字
let str="10000";
let num = +str;
console.log(num); // 10000
Falsy和Truthy值转boolean
Falsy为Javascript中所有可以转换为false的值的统称，共8个：false本身、空字符串、null、undefined、NaN、数字0、数字-0、大数字0n。
除Falsy值外其他所有值都是Truthy
let falseNum = 0;
let falseStr = "";
let falseUndefined;
let falseNull = null;
let falseNaN = 0/0;
let trueNum = 1;
let trueStr = "何方";
let trueObj = {name:"何方"};
let trueArr = ["前端","后端"];
console.log("falseNum", !!falseNum); // false
console.log("falseStr", !!falseStr); // false
console.log("falseUndefined", !!falseUndefined); // false
console.log("falseNaN",!!falseNaN); // false
console.log("trueNum",!!trueNum); // true
console.log("trueStr",!!trueStr); // true
console.log("trueObj",!!trueObj); // true
console.log("trueArr",!!trueArr); // true
交换对象键值
let obj = {
key1: "value1",
key2: "value2"
};
let revert = {};
Object.entries(obj).forEach(([key, value]) => revert[value] = key);
console.log(revert);
数组去重
值类型数组
let arrNum = [
1, 2, 3, 4, 5, 6, 7, 8, 9, 0,
1, 2, 3, 4, 5, 6, 7, 8, 9, 0
];
let arrString = [
"1", "2", "3", "4", "5", "6", "7", "8", "9", "0",
"1", "2", "3", "4", "5", "6", "7", "8", "9", "0"
];
let arrMixed = [
1, "1", "2", true, false, false, 1, 2, "2"
];
arrNum = Array.from(new Set(arrNum));
arrString = [...new Set(arrString)];
arrMixed = [...new Set(arrMixed)];
console.log(arrNum); // [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
console.log(arrString); // ["1", "2", "3", "4", "5", "6", "7", "8", "9", "0"]
console.log(arrMixed); // [1, "1", "2", true, false, 2]
引用类型数组
let arrObj = [
{name: "何方"},
{name: "王二"},
{name: "何方"},
{name: "何方"},
{name: "何方"},
{name: "何方"},
{name: "王二"},
{name: "王二"},
{name: "王二"},
{name: "王二"},
];
let arrObj2 = [];
arrObj.forEach(item => {
arrObj2.find(find => find.name === item.name) || arrObj2.push(item)
});
console.log(arrObj2);
原文地址：https://www.toutiao.com/a6914823899238875655/