diff --git a/notes/ES6_基础.md b/notes/ES6_基础.md index 675df08..1e087d9 100644 --- a/notes/ES6_基础.md +++ b/notes/ES6_基础.md @@ -233,11 +233,11 @@ list.forEach(function (func) { ```javascript let msg = "Hello world!"; console.log(msg.startsWith("Hello")); // true -console.log(msg.endsWith("!")); // true -console.log(msg.includes("o")); // true -console.log(msg.startsWith("o", 4)); // true -console.log(msg.endsWith("o", 8)); // true -console.log(msg.includes("o", 8)); // false +console.log(msg.endsWith("!")); // true +console.log(msg.includes("o")); // true +console.log(msg.startsWith("o", 4)); // true +console.log(msg.endsWith("o", 8)); // true +console.log(msg.includes("o", 8)); // false ``` **2. 复制字符串** @@ -257,10 +257,10 @@ console.log("hello".repeat(2)); ```javascript 'x'.padStart(5, 'ab'); // 'ababx' -'x'.padEnd(5, 'ab'); // 'xabab' +'x'.padEnd(5, 'ab'); // 'xabab' 'xxx'.padStart(2, 'ab'); // 'xxx' -'x'.padStart(4); // ' x' +'x'.padStart(4); // ' x' ``` ### 2.2 模板字面量 @@ -286,14 +286,14 @@ console.log(message02); // "10 items cost $2.50." let message03 = `Multiline string`; console.log(message03); // Hello, - // string + // string // 4.多行字符串与模板嵌套 let fullName = "Nicholas", message04 = `Hello, my name is ${fullName}.`; console.log(message04); // Hello, - // my name is Nicholas. + // my name is Nicholas. ``` @@ -310,10 +310,10 @@ function request(url, timeout = 2000, callback = function() {}) { callback(); } -request("GitHub"); // url: GitHub, timeout: 2000 -request("GitHub", undefined); // url: GitHub, timeout: 2000 -request("GitHub", null); // url: GitHub, timeout: null -request("GitHub", 5000); // url: GitHub, timeout: 5000 +request("GitHub"); // url: GitHub, timeout: 2000 +request("GitHub", undefined); // url: GitHub, timeout: 2000 +request("GitHub", null); // url: GitHub, timeout: null +request("GitHub", 5000); // url: GitHub, timeout: 5000 request("GitHub", 5000, () => console.log("超时异常")); // url: GitHub, timeout: 5000 超时异常 ``` @@ -483,24 +483,24 @@ var person = { 在 ES5 之前,我们通常使用 `===` 进行相等性判断,它能满足大多数的使用场景,但也会出现一些不准确的结果: ```java --0 === +0 //true +-0 === +0 //true NaN === NaN //false ``` 大多数时候,我们并不需要区分出正负零,但在有的计算中是有必要进行区分的,如下分别使用正负零得到的是完全相反的结果: ```javascript -1/0 // Infinity +1/0 // Infinity 1/-0 // -Infinity ``` 为了满足这种需求,ES6 引入了 `Object.is()` ,它在效果上类似于 `===` 运算符,但能准确的区分正负零和 NaN 的等值比较: ```javascript -Object.is(+0, -0) // false +Object.is(+0, -0) // false Object.is(NaN, NaN) // true -Object.is(5, 5) // true -Object.is(5, "5") // false +Object.is(5, 5) // true +Object.is(5, "5") // false ``` ### 4.3 属性复制 @@ -647,7 +647,7 @@ let person = { }; let {name, age} = person; console.log(name); // "heibaiying" -console.log(age); // "18" +console.log(age); // "18" ``` ES6 还支持为待解构的变量传入默认值: @@ -695,7 +695,7 @@ console.log(teacherName); // "heibai" ```java let colors = ["red", "green", "blue"]; let [firstColor, secondColor] = colors; -console.log(firstColor); // "red" +console.log(firstColor); // "red" console.log(secondColor); // "green" let colors = ["red", "green", "blue"]; @@ -708,13 +708,13 @@ console.log(thirdColor); // "blue ```java // 设置默认值 let [firstColor, secondColor = "green"] = ["red"]; -console.log(firstColor); // "red" +console.log(firstColor); // "red" console.log(secondColor); // "green" // 嵌套解构 let colors = ["red", ["green", "lightgreen"], "blue"]; let [firstColor, [secondColor]] = colors; -console.log(firstColor); // "red" +console.log(firstColor); // "red" console.log(secondColor); // "green" ``` @@ -1007,8 +1007,8 @@ map01.clear(); // 2.由数组初始化map let map02 = new Map([["name", "Nicholas"], ["age", 25]]); console.log(map02.get("name")); // "Nicholas" -console.log(map02.get("age")); // 25 -console.log(map02.size); // 2 +console.log(map02.get("age")); // 25 +console.log(map02.size); // 2 // 3.进行遍历 let map03 = new Map([["name", "Nicholas"], ["age", 25]]); @@ -1263,10 +1263,10 @@ ES6 支持对象代理,你可以通过 `new Proxy(target)` 来基于目标对 let target = {}; let proxy = new Proxy(target, {}); proxy.name = "proxy"; -console.log(proxy.name); // "proxy" +console.log(proxy.name); // "proxy" console.log(target.name); // "proxy" target.name = "target"; -console.log(proxy.name); // "target" +console.log(proxy.name); // "target" console.log(target.name); // "target" ``` @@ -1413,7 +1413,7 @@ export { sum as add }; // 对导入名称进行重命名 import { add as sum } from "./example.js"; console.log(typeof add); // "undefined" -console.log(sum(1, 2)); // 3 +console.log(sum(1, 2)); // 3 ``` ### 12.5 导入导出默认值